JEE Main & Advanced Physics Electrostatics & Capacitance Question Bank

done Electric Field and Potential Total Questions - 210

• question_answer1)
  A charge q is placed at the centre of the line joining two equal charges Q. The system of the three charges will be in equilibrium, if \[q\] is equal to             [IIT 1987; CBSE PMT 1995; Bihar MEE 1995; CPMT 1999; MP PET 1999; MP PMT 1999, 2000; RPET 1999;  KCET 2001; AIEEE 2002; AFMC 2002; Kerala PMT 2004; J & K CET 2004]
  A)
                                                       \[-\frac{Q}{2}\]                    done clear
  B)
             \[-\frac{Q}{4}\] done clear
  C)
                     \[+\frac{Q}{4}\] done clear
  D)
                                       \[+\frac{Q}{2}\] done clear
  View Solution play_arrow

• question_answer2)
  Inside a hollow charged spherical conductor, the potential [CPMT 1971; MP PMT 1986; RPMT 1997]
  A)
                     Is constant done clear
  B)
                     Varies directly as the distance from the centre done clear
  C)
                     Varies inversely as the distance from the centre done clear
  D)
                     Varies inversely as the square of the distance from the centre done clear
  View Solution play_arrow

• question_answer3)
  Two small spheres each carrying a charge \[q\] are placed \[r\] metre apart. If one of the spheres is taken around the other one in a circular path of radius \[r\], the work done will be equal to             [CPMT 1975, 91, 2001; NCERT 1980, 83; EAMCET 1994; MP PET 1995; MNR 1998;  Pb. PMT 2000]
  A)
                                                       Force between them \[\times \,r\] done clear
  B)
                     Force between them \[\times \,2\pi r\] done clear
  C)
                     Force between them \[/2\pi r\] done clear
  D)
                     Zero done clear
  View Solution play_arrow

• question_answer4)
  The electric charge in uniform motion produces                                                                [CPMT 1971]
  A)
                     An electric field only  done clear
  B)
                     A magnetic field only done clear
  C)
                     Both electric and magnetic field done clear
  D)
                     Neither electric nor magnetic field done clear
  View Solution play_arrow

• question_answer5)
  Two charged spheres of radii 10 cm and 15 cm are connected by a thin wire. No current will flow, if they have                                                                                                                            [MP PET 1991; CPMT 1975]
  A)
                     The same charge on each done clear
  B)
                     The same potential done clear
  C)
                     The same energy done clear
  D)
                     The same field on their surfaces done clear
  View Solution play_arrow

• question_answer6)
  The electric field inside a spherical shell of uniform surface charge density is                                                                                                                                     [CPMT 1982; MP PET 1994; RPET 2000]
  A)
                     Zero done clear
  B)
                     Constant, less than zero done clear
  C)
                     Directly proportional to the distance from the centre done clear
  D)
                     None of the above done clear
  View Solution play_arrow

• question_answer7)
  The electric potential \[V\] at any point O (x, y, z all in metres) in space is given by \[V=4{{x}^{2}}\,volt\]. The electric field at the point \[(1m,\,0,\,2m)\] in \[volt/metre\] is                                                         [IIT 1992; RPET 1999; MP PMT 2001]
  A)
                     8 along negative \[X-\]axis done clear
  B)
                     8 along positive \[X-\]axis done clear
  C)
                     16 along negative \[X-\]axis done clear
  D)
                     16 along positive \[Z-\]axis done clear
  View Solution play_arrow

• question_answer8)
  A hollow metal sphere of radius 5 cm is charged so that the potential on its surface is 10 V.  The potential at the centre of the sphere is                                   [IIT 1983; MNR 1990; MP PET/PMT 2000; DPMT 2004]
  A)
                     0 V done clear
  B)
                                       10 V done clear
  C)
                     Same as at point 5 cm away from the surface done clear
  D)
                     Same as at point 25 cm away from the surface done clear
  View Solution play_arrow

• question_answer9)
  If a unit positive charge is taken from one point to another over an equipotential surface, then                                                                                                                                                 [KCET 1994; CPMT 1997; CBSE PMT 2000]
  A)
                     Work is done on the charge done clear
  B)
                     Work is done by the charge done clear
  C)
                     Work done is constant done clear
  D)
                     No work is done done clear
  View Solution play_arrow

• question_answer10)
  Electric lines of force about negative point charge are                                                       [MP PMT 1987]
  A)
                     Circular, anticlockwise       done clear
  B)
             Circular, clockwise done clear
  C)
                     Radial, inward done clear
  D)
             Radial, outward done clear
  View Solution play_arrow

• question_answer11)
  Charges of \[+\frac{10}{3}\times {{10}^{-9}}C\] are placed at each of the four corners of a square of side \[8\,cm\]. The potential at the intersection of the diagonals is                                                                                         [BIT 1993]
  A)
                     \[150\sqrt{2}\,volt\]  done clear
  B)
             \[1500\sqrt{2}\,volt\] done clear
  C)
                     \[900\sqrt{2}\,volt\]  done clear
  D)
             \[900\,volt\] done clear
  View Solution play_arrow

• question_answer12)
  A uniform electric field having a magnitude \[{{E}_{0}}\] and direction along the positive \[X-\]axis exists. If the potential \[V\] is zero at \[x=0\], then its value at \[X=+x\] will be [MP PMT 1987]
  A)
                     \[{{V}_{(x)}}=+x{{E}_{0}}\] done clear
  B)
                                       \[{{V}_{x}}=-x{{E}_{0}}\] done clear
  C)
                     \[{{V}_{x}}=+{{x}^{2}}{{E}_{0}}\] done clear
  D)
                                       \[{{V}_{x}}=-{{x}^{2}}{{E}_{0}}\] done clear
  View Solution play_arrow

• question_answer13)
  Three charges \[2q,\,-q,\,-q\] are located at the vertices of an equilateral triangle. At the centre of the triangle [MP PET 1985; J & K CET 2004]
  A)
                     The field is zero but potential is non-zero done clear
  B)
                     The field is non-zero but potential is zero done clear
  C)
                     Both field and potential are zero done clear
  D)
                     Both field and potential are non-zero done clear
  View Solution play_arrow

• question_answer14)
  Figure shows the electric lines of force emerging from a charged body. If the electric field at A and B are \[{{E}_{A}}\] and \[{{E}_{B}}\] respectively and if the displacement between A and B is \[r\] then                                                                                                                                                                                                                       [CPMT 1986, 88]
  A)
                     \[{{E}_{A}}>{{E}_{B}}\]     done clear
  B)
             \[{{E}_{A}}<{{E}_{B}}\] done clear
  C)
                     \[{{E}_{A}}=\frac{{{E}_{B}}}{r}\] done clear
  D)
                                       \[{{E}_{A}}=\frac{{{E}_{B}}}{{{r}^{2}}}\] done clear
  View Solution play_arrow

• question_answer15)
  ABC is an equilateral triangle. Charges \[+\,q\] are placed at each corner. The electric intensity at \[O\] will be                                                                                                                                  [CPMT 1985; AIEEE 2002]
  A)
                     \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{q}{{{r}^{2}}}\] done clear
  B)
                     \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{q}{r}\] done clear
  C)
                     Zero done clear
  D)
                     \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{3q}{{{r}^{2}}}\] done clear
  View Solution play_arrow

• question_answer16)
  In the electric field of a point charge \[q\], a certain charge is carried from point \[A\] to \[B\], \[C\], \[D\] and \[E\]. Then the work done                                                                                                                                       [NCERT 1980]
  A)
                     Is least along the path \[AB\] done clear
  B)
                     Is least along the path \[AD\] done clear
  C)
                     Is zero along all the paths \[AB,\ AC,\ AD\] and \[AE\] done clear
  D)
                     Is least along \[AE\] done clear
  View Solution play_arrow

• question_answer17)
  The magnitude of electric field intensity \[E\] is such that, an electron placed in it would experience an electrical force equal to its weight is given by                                                [CPMT 1975, 80; AFMC 2001; BCECE 2003]
  A)
                     \[mge\] done clear
  B)
                                       \[\frac{mg}{e}\] done clear
  C)
                     \[\frac{e}{mg}\] done clear
  D)
                                       \[\frac{{{e}^{2}}}{{{m}^{2}}}g\] done clear
  View Solution play_arrow

• question_answer18)
  A conductor with a positive charge
  A)
                     Is always at \[+\,ve\] potential done clear
  B)
                     Is always at zero potential done clear
  C)
                     Is always at negative potential done clear
  D)
                     May be at , zero or  potential done clear
  View Solution play_arrow

• question_answer19)
  An electron and a proton are in a uniform electric field, the ratio of their accelerations will be                                                                       [NCERT 1984; MP PET 2002]
  A)
                     Zero done clear
  B)
                                       Unity done clear
  C)
                     The ratio of the masses of proton and electron done clear
  D)
                     The ratio of the masses of electron and proton done clear
  View Solution play_arrow

• question_answer20)
  Two parallel plates have equal and opposite charge. When the space between them is evacuated, the electric field between the plates is \[2\times {{10}^{5}}V/m\]. When the space is filled with dielectric, the electric field becomes\[1\times {{10}^{5}}V/m\]. The dielectric constant of the dielectric material      [MP PET 1989]
  A)
                     1/2 done clear
  B)
                                       1 done clear
  C)
                     2 done clear
  D)
                                       3 done clear
  View Solution play_arrow

• question_answer21)
  . The insulation property of air breaks down at \[E=3\times {{10}^{6}}\] volt/metre. The maximum charge that can be given to a sphere of diameter \[5\,m\] is approximately (in coulombs) [MP PMT 1990]
  A)
                     \[2\times {{10}^{-2}}\] done clear
  B)
                                       \[2\times {{10}^{-3}}\] done clear
  C)
                     \[2\times {{10}^{-4}}\] done clear
  D)
                                       \[2\times {{10}^{-5}}\] done clear
  View Solution play_arrow

• question_answer22)
  The distance between the two charges \[25\mu C\] and \[36\mu C\] is \[11cm\] At what point on the line joining the two, the intensity will be zero
  A)
                     At a distance of \[5\,cm\]from \[25\mu C\] done clear
  B)
                     At a distance of \[5\,cm\]from \[36\mu C\] done clear
  C)
                     At a distance of \[10\,cm\]from \[25\mu C\] done clear
  D)
                     At a distance of \[11\,cm\]from \[36\mu C\] done clear
  View Solution play_arrow

• question_answer23)
  Two spheres \[A\]and \[B\] of radius \[4cm\] and \[6cm\] are given charges of \[80\mu c\] and \[40\mu c\]respectively. If they are connected by a fine wire, the amount of charge flowing from one to the other is                                                                     [MP PET 1991]
  A)
                     \[20\mu C\]from \[A\]to \[B\]                                  done clear
  B)
             \[16\mu C\] from \[A\]to \[B\] done clear
  C)
                     \[32\mu C\]from \[B\] to \[A\]                                 done clear
  D)
             \[32\mu C\] from \[A\]to \[B\] done clear
  View Solution play_arrow

• question_answer24)
  A charge particle is free to move in an electric field. It will travel                                                 [IIT 1979]
  A)
                     Always along a line of force done clear
  B)
                     Along a line of force, if its initial velocity is zero done clear
  C)
                     Along a line of force, if it has some initial velocity in the direction of an acute angle with the line of force done clear
  D)
                     None of the above done clear
  View Solution play_arrow

• question_answer25)
  If \[E\] is the electric field intensity of an electrostatic field, then the electrostatic energy density is proportional to                                                                                          [MP PMT 2003]
  A)
                     \[E\] done clear
  B)
                                       \[{{E}^{2}}\] done clear
  C)
                     \[1/{{E}^{2}}\] done clear
  D)
                                       \[{{E}^{3}}\] done clear
  View Solution play_arrow

• question_answer26)
  A metallic sphere has a charge of \[10\mu C\]. A unit negative charge is brought from \[A\]to \[B\] both \[100\,cm\] away from the sphere but A being east of it while \[B\]being on west. The net work done is
  A)
                     Zero done clear
  B)
                                       \[2/10\ joule\] done clear
  C)
                     \[-2/10\ joule\] done clear
  D)
                            \[-1/10\ joule\] done clear
  View Solution play_arrow

• question_answer27)
  Two charges \[+4e\] and \[+e\]are at a distance\[x\] apart. At what distance, a charge \[q\] must be placed from charge \[+e\]so that it is in equilibrium
  A)
                     \[x/2\] done clear
  B)
                                       \[2x/3\] done clear
  C)
                     \[x/3\] done clear
  D)
                                       \[x/6\] done clear
  View Solution play_arrow

• question_answer28)
  An uncharged sphere of metal is placed in between two charged plates as shown. The lines of force look like [MP PMT 1985; KCET 2004]                                                      
  A)
                     \[A\] done clear
  B)
                                       \[B\] done clear
  C)
                     \[C\] done clear
  D)
                                       \[D\] done clear
  View Solution play_arrow

• question_answer29)
  The intensity of electric field required to balance a proton of mass \[1.7\times {{10}^{-27}}kg\] and charge\[1.6\times {{10}^{-19}}C\] is nearly
  A)
             \[1\times {{10}^{-7}}\ V/m\] done clear
  B)
                                       \[1\times {{10}^{-5}}\ V/m\] done clear
  C)
                     \[1\times {{10}^{7}}\ V/m\] done clear
  D)
                                       \[1\times {{10}^{5}}\ V/m\] done clear
  View Solution play_arrow

• question_answer30)
  On rotating a point charge having a charge q around a charge Q in a circle of radius r. The work done will be [CPMT 1990, 97; MP PET 1993; AIIMS 1997; DCE 2003; KCET 2005]
  A)
                     \[q\times 2\pi r\] done clear
  B)
                                       \[\frac{q\times 2\pi Q}{r}\] done clear
  C)
                     Zero done clear
  D)
                                       \[\frac{Q}{2{{\varepsilon }_{0}}r}\] done clear
  View Solution play_arrow

• question_answer31)
  Two point charges \[Q\] and ? 3Q are placed at some distance apart. If the electric field at the location of \[Q\] is \[E\] then at the locality of \[-3Q\], it is                                                            [BIT 1987]
  A)
                     \[-E\] done clear
  B)
                                       \[E/3\] done clear
  C)
                     \[-3E\] done clear
  D)
                                       \[-E/3\] done clear
  View Solution play_arrow

• question_answer32)
  The number of electrons to be put on a spherical conductor of radius\[0.1\,m\] to produce an electric field of \[0.036N/C\] just above its surface is [MNR 1994; KCET (Engg.)  1999; MH CET (Med.) 2001]
  A)
                                                       \[2.7\times {{10}^{5}}\] done clear
  B)
                                       \[2.6\times {{10}^{5}}\] done clear
  C)
                     \[2.5\times {{10}^{5}}\] done clear
  D)
                                       \[2.4\times {{10}^{5}}\] done clear
  View Solution play_arrow

• question_answer33)
  Two plates are \[2\,cm\] apart, a potential difference of\[10\ volt\] is applied between them, the electric field between the plates is                                                                                                    [MP PET 1994; DPMT 2002]
  A)
                     \[20\ N/C\] done clear
  B)
                                       \[500\,N/C\] done clear
  C)
                     \[5\,N/C\] done clear
  D)
                                       \[250\ N/C\] done clear
  View Solution play_arrow

• question_answer34)
  The intensity of the electric field required to keep a water drop of radius \[{{10}^{-5}}cm\] just suspended in air when charged with one electron is approximately [MP PMT 1994]
  A)
             \[260\,volt/cm\] done clear
  B)
                                       \[260\,newton/coulomb\] done clear
  C)
                     \[130\,volt/cm\] done clear
  D)
                                       \[130\,newton/coulomb\]            \[(g=10\,newton/kg,\,e=1.6\times {{10}^{-19}}coulomb)\] done clear
  View Solution play_arrow

• question_answer35)
  Conduction electrons are almost uniformly distributed within a conducting plate. When placed in an electrostatic field \[\overrightarrow{E}\], the electric field within the plate                              [MP PMT 1994]
  A)
                     Is zero done clear
  B)
                                               Depends upon \[E\] done clear
  C)
                     Depends upon \[\overrightarrow{E}\] done clear
  D)
                     Depends upon the atomic number of the conducting element done clear
  View Solution play_arrow

• question_answer36)
  Three particles, each having a charge of \[10\,\mu C\] are placed at the corners of an equilateral triangle of side \[10\,cm\]. The electrostatic potential energy of the system is (Given \[\frac{1}{4\pi {{\varepsilon }_{0}}}=9\times {{10}^{9}}N-{{m}^{2}}/{{C}^{2}}\])                                                           [MP PMT 1994]
  A)
                                                                Zero done clear
  B)
                                                  Infinite done clear
  C)
                                                                \[27\,J\] done clear
  D)
                                                  \[100\,J\] done clear
  View Solution play_arrow

• question_answer37)
  The electric field near a conducting surface having a uniform surface charge density \[\sigma \] is given by           [MP PMT 1994]
  A)
                                                                \[\frac{\sigma }{{{\varepsilon }_{0}}}\] and is parallel to the surface done clear
  B)
                                                                \[\frac{2\sigma }{{{\varepsilon }_{0}}}\] and is parallel to the surface done clear
  C)
                                                                \[\frac{\sigma }{{{\varepsilon }_{0}}}\] and is normal to the surface done clear
  D)
                                                                \[\frac{2\sigma }{{{\varepsilon }_{0}}}\] and is normal to the surface done clear
  View Solution play_arrow

• question_answer38)
  There is an electric field \[E\] in X-direction. If the work done on moving a charge \[0.2\,C\] through a distance of \[2\,m\] along a line making an angle \[60{}^\circ \] with the X-axis is 4.0, what is the value of \[E\]                                             [CBSE PMT 1995]
  A)
                     \[\sqrt{3}\,N/C\] done clear
  B)
                                                  \[4\,N/C\] done clear
  C)
                                                                \[5\,N/C\] done clear
  D)
                                                  None of these done clear
  View Solution play_arrow

• question_answer39)
  Four equal charges \[Q\] are placed at the four corners of a square of each side is \['a'\]. Work done in removing a charge ? Q from its centre to infinity is                                                   [AIIMS 1995]
  A)
                     0                                         done clear
  B)
                     \[\frac{\sqrt{2}{{Q}^{2}}}{4\pi {{\varepsilon }_{0}}a}\] done clear
  C)
                                                                \[\frac{\sqrt{2}{{Q}^{2}}}{\pi {{\varepsilon }_{0}}a}\] done clear
  D)
                                                  \[\frac{{{Q}^{2}}}{2\pi {{\varepsilon }_{0}}a}\] done clear
  View Solution play_arrow

• question_answer40)
  A particle \[A\] has charge \[+q\] and a particle \[B\] has charge \[+\,4q\] with each of them having the same mass \[m\]. When allowed to fall from rest through the same electric potential difference, the ratio of their speed \[\frac{{{v}_{A}}}{{{v}_{B}}}\] will become                                                                                                                                 [BHU 1995; MNR 1991; UPSEAT 2000; Pb PET 2004]                   
  A)
                     \[2:1\] done clear
  B)
                                                  \[1:2\] done clear
  C)
                                                                \[1:4\] done clear
  D)
                                                  \[4:1\] done clear
  View Solution play_arrow

• question_answer41)
  Deutron and \[\alpha -\]particle are put \[1\,{AA}\] apart in air. Magnitude of intensity of electric field due to deutron at \[\alpha -\]particle is                                             [MP PET 1995]
  A)
                                                                Zero done clear
  B)
                                                                \[2.88\times {{10}^{11}}\,newton/coulomb\] done clear
  C)
                                                                \[1.44\times {{10}^{11}}\,newton/coulomb\] done clear
  D)
                                                                \[5.76\times {{10}^{11}}\,newton/coulomb\] done clear
  View Solution play_arrow

• question_answer42)
  Angle between equipotential surface and lines of force is                    [MP PET 1995]
  A)
                                                                Zero done clear
  B)
                                                  \[180{}^\circ \] done clear
  C)
                                                                \[90{}^\circ \] done clear
  D)
                                                  \[45{}^\circ \] done clear
  View Solution play_arrow

• question_answer43)
  Below figures (1) and (2) represent lines of force. Which is correct statement     [MP PET 1995]
  A)
                                                                Figure (1) represents magnetic lines of force done clear
  B)
                                                                Figure (2) represents magnetic lines of force done clear
  C)
                                                                Figure (1) represents electric lines of force done clear
  D)
                                                                Both figure (1) and figure (2) represent magnetic lines of force done clear
  View Solution play_arrow

• question_answer44)
  The unit of electric field is not equivalent to [MP PMT 1995]
  A)
                                                                \[N/C\] done clear
  B)
                                               \[J/C\] done clear
  C)
                                                                \[V/m\] done clear
  D)
                                               \[J/C-m\] done clear
  View Solution play_arrow

• question_answer45)
  A flat circular disc has a charge \[+Q\] uniformly distributed on the disc. A charge \[+q\] is thrown with kinetic energy \[E\]towards the disc along its normal axis. The charge \[q\]will [MP PMT 1995]
  A)
                                                                Hit the disc at the centre done clear
  B)
                                                                Return back along its path after touching the disc done clear
  C)
                                                                Return back along its path without touching the disc done clear
  D)
                                                                Any of the above three situations is possible depending on the magnitude of E done clear
  View Solution play_arrow

• question_answer46)
  At a certain distance from a point charge the electric field is \[500\,V/m\] and the potential is \[3000\,V\]. What is this distance  [MP PMT 1995; Pb. PMT 2001; AFMC 2001]
  A)
                                                                \[6\,m\] done clear
  B)
                                               \[12\,m\] done clear
  C)
                                                                \[36\,m\] done clear
  D)
                                               \[144\,m\] done clear
  View Solution play_arrow

• question_answer47)
  The magnitude of electric field \[E\] in the annular region of a charged cylindrical capacitor                                           [IIT 1996]
  A)
                                                                Is same throughout done clear
  B)
                                                                Is higher near the outer cylinder than near the inner cylinder done clear
  C)
                                                                Varies as \[1/r\], where \[r\] is the distance from the axis done clear
  D)
                                                                Varies as \[1/{{r}^{2}}\], where \[r\] is the distance from the axis done clear
  View Solution play_arrow

• question_answer48)
  A metallic solid sphere is placed in a uniform electric field. The lines of force follow the path(s) shown in figure as                                                                                                                        [IIT 1996]
  A)
                     1 done clear
  B)
                                       2 done clear
  C)
                     3 done clear
  D)
                                       4 done clear
  View Solution play_arrow

• question_answer49)
  The distance between a proton and electron both having a charge \[1.6\times {{10}^{-19}}coulomb\], of a hydrogen atom is \[{{10}^{-10}}metre\]. The value of intensity of electric field produced on electron due to proton will be                   [MP PET 1996]
  A)
                     \[2.304\times {{10}^{-10}}N/C\] done clear
  B)
                                       \[14.4\,V/m\] done clear
  C)
                     \[16\,V/m\] done clear
  D)
                                       \[1.44\times {{10}^{11}}N/C\] done clear
  View Solution play_arrow

• question_answer50)
  What is the magnitude of a point charge due to which the electric field \[30\,cm\] away has the magnitude \[2\,newton/coulomb\] \[[1/4\pi {{\varepsilon }_{0}}=9\times {{10}^{9}}N{{m}^{2}}/{{C}^{2}}]\]                                                                                                       [MP PMT 1996]
  A)
                     \[2\times {{10}^{-11}}coulomb\] done clear
  B)
                                       \[3\times {{10}^{-11}}coulomb\] done clear
  C)
                     \[5\times {{10}^{-11}}coulomb\]                              done clear
  D)
             \[9\times {{10}^{-11}}coulomb\] done clear
  View Solution play_arrow

• question_answer51)
  Two charge \[+\,q\] and \[-\,q\] are situated at a certain distance.  At the point exactly midway between them
  A)
                     Electric field and potential both are zero done clear
  B)
                     Electric field is zero but potential is not zero done clear
  C)
                     Electric field is not zero but potential is zero done clear
  D)
                     Neither electric field nor potential is zero done clear
  View Solution play_arrow

• question_answer52)
  Two positive charges of 20 \[coulomb\] and \[Q\ coulomb\]are situated at a distance of \[60\,cm\]. The neutral point between them is at a distance of \[20\,cm\] from the \[20\,coulomb\] charge. Charge \[Q\] is
  A)
                     \[30\,C\] done clear
  B)
                                       \[40\,C\] done clear
  C)
                     \[60\,C\] done clear
  D)
                                       \[80\,C\] done clear
  View Solution play_arrow

• question_answer53)
  In the figure the charge \[Q\] is at the centre of the circle. Work done is maximum when another charge is taken from point \[P\] to
  A)
                     \[K\] done clear
  B)
                     \[L\] done clear
  C)
                     \[M\] done clear
  D)
                     \[N\] done clear
  View Solution play_arrow

• question_answer54)
  A mass \[m=20\,g\] has a charge \[q=3.0\,mC\]. It moves with a velocity of \[20\,m/s\] and enters a region of electric field of \[80\,N/C\]in the same direction as the velocity of the mass. The velocity of the mass after 3 seconds in this region is
  A)
             \[80\,m/s\] done clear
  B)
                                       \[56\,m/s\] done clear
  C)
                     \[44\,m/s\] done clear
  D)
                                       \[40\,m/s\] done clear
  View Solution play_arrow

• question_answer55)
  Four identical charges \[+\,50\,\mu C\] each are placed, one at each corner of a square of side \[2\,m\]. How much external energy is required to bring another charge of \[+\,50\,\mu C\] from infinity to the centre of the square            \[\left( \text{Given}\frac{\text{1}}{\text{4}\pi {{\varepsilon }_{\text{0}}}}=9\times {{10}^{9}}\frac{N{{m}^{2}}}{{{C}^{2}}} \right)\]
  A)
                     \[64\,J\] done clear
  B)
             \[41\,J\] done clear
  C)
                     \[16\,J\] done clear
  D)
                                       \[10\,J\] done clear
  View Solution play_arrow

• question_answer56)
  In Millikan's oil drop experiment an oil drop carrying a charge Q is held stationary by a potential difference \[2400\,V\] between the plates. To keep a drop of half the radius stationary the potential difference had to be made \[600\,V\]. What is the charge on the second drop            [MP PET 1997]
  A)
                     \[\frac{Q}{4}\] done clear
  B)
                                       \[\frac{Q}{2}\] done clear
  C)
                     \[Q\] done clear
  D)
                                       \[\frac{3Q}{2}\] done clear
  View Solution play_arrow

• question_answer57)
  A charge of \[5\,C\] experiences a force of \[5000\,N\] when it is kept in a uniform electric field. What is the potential difference between two points separated by a distance of \[1\,cm\]                                      [MP PET 1997]
  A)
                     \[10\,V\] done clear
  B)
             \[250\,V\] done clear
  C)
                     \[1000\,V\] done clear
  D)
                                       \[2500\,V\] done clear
  View Solution play_arrow

• question_answer58)
  Two insulated charged conducting spheres of radii \[20\,cm\] and \[15\,cm\]respectively and having an equal charge of \[10\,C\] are connected by a copper wire and then they are separated. Then                                                [MP PET 1997]
  A)
                     Both the spheres will have the same charge of \[10\,C\] done clear
  B)
                     Surface charge density on the \[20\,cm\] sphere will be greater than that on the \[15\,cm\] sphere done clear
  C)
                     Surface charge density on the \[15\,cm\] sphere will be greater than that on the \[20\,cm\] sphere done clear
  D)
                     Surface charge density on the two spheres will be equal done clear
  View Solution play_arrow

• question_answer59)
  Equal charges \[q\] are placed at the vertices \[A\] and \[B\] of an equilateral triangle \[ABC\] of side \[a\]. The magnitude of electric field at the point \[C\] is                                                   [MP PMT 1997]
  A)
                     \[\frac{q}{4\pi {{\varepsilon }_{0}}{{a}^{2}}}\] done clear
  B)
                                       \[\frac{\sqrt{2}\,q}{4\pi {{\varepsilon }_{0}}{{a}^{2}}}\] done clear
  C)
                     \[\frac{\sqrt{3}\,q}{4\pi {{\varepsilon }_{0}}{{a}^{2}}}\] done clear
  D)
                                       \[\frac{q}{2\pi {{\varepsilon }_{0}}{{a}^{2}}}\] done clear
  View Solution play_arrow

• question_answer60)
  Two equal charges \[q\] are placed at a distance of \[2a\] and a third charge \[-2q\] is placed at the midpoint. The potential energy of the system is                                                             [MP PMT 1997]
  A)
                     \[\frac{{{q}^{2}}}{8\pi {{\varepsilon }_{0}}a}\] done clear
  B)
                                       \[\frac{6{{q}^{2}}}{8\pi {{\varepsilon }_{0}}a}\] done clear
  C)
                     \[-\frac{7{{q}^{2}}}{8\pi {{\varepsilon }_{0}}a}\] done clear
  D)
                                       \[\frac{9{{q}^{2}}}{8\pi {{\varepsilon }_{0}}a}\] done clear
  View Solution play_arrow

• question_answer61)
  Two point charges \[100\,\mu \,C\] and \[5\,\mu \,C\] are placed at points \[A\] and \[B\] respectively with \[AB=40\,cm\]. The work done by external force in displacing the charge \[5\,\mu \,C\] from \[B\] to \[C\], where \[BC=30\,cm\], angle \[ABC=\frac{\pi }{2}\] and \[\frac{1}{4\pi {{\varepsilon }_{0}}}=9\times {{10}^{9}}N{{m}^{2}}/{{C}^{2}}\]                                                               [MP PMT 1997]
  A)
                     \[9\,J\] done clear
  B)
                                       \[\frac{81}{20}J\] done clear
  C)
                     \[\frac{9}{25}J\] done clear
  D)
                                       \[-\frac{9}{4}J\] done clear
  View Solution play_arrow

• question_answer62)
  The unit of intensity of electric field is      [MP PMT/PET 1998]
  A)
                     \[Newton/Coulomb\] done clear
  B)
                                       \[Joule/Coulomb\] done clear
  C)
                     \[Volt-metre\] done clear
  D)
                                       \[Newton/metre\] done clear
  View Solution play_arrow

• question_answer63)
  Equal charges are given to two spheres of different radii. The potential will          [MP PMT/PET 1998; MH CET 2000]
  A)
                     Be more on the smaller sphere done clear
  B)
                     Be more on the bigger sphere done clear
  C)
                     Be equal on both the spheres done clear
  D)
                     Depend on the nature of the materials of the spheres done clear
  View Solution play_arrow

• question_answer64)
  An alpha particle is accelerated through a potential difference of \[{{10}^{6}}\,volt\]. Its kinetic energy will be                                                                                   [MP PMT/PET 1998]
  A)
                     \[1\,MeV\] done clear
  B)
                                       \[2\,MeV\] done clear
  C)
                     \[4\,MeV\] done clear
  D)
                                       \[8\,MeV\] done clear
  View Solution play_arrow

• question_answer65)
  A charge of \[5\,C\] is given a displacement of \[0.5\,m\]. The work done in the process is \[10\,J\]. The potential difference between the two points will be                                          [MP PET 1999]
  A)
                     \[2\,V\] done clear
  B)
                                       \[0.25\,V\] done clear
  C)
                     \[1\,V\] done clear
  D)
                                       \[25\,V\] done clear
  View Solution play_arrow

• question_answer66)
  The electric potential \[V\] is given as a function of distance \[x\] (metre) by \[V=(5{{x}^{2}}+10x-9)\,volt\]. Value of electric field at \[x=1\] is                                         [MP PET 1999]
  A)
                     \[20\,V/m\] done clear
  B)
                                       \[6\,V/m\] done clear
  C)
                     \[11\,V/m\] done clear
  D)
                                       \[-23\,V/m\] done clear
  View Solution play_arrow

• question_answer67)
  Two metal pieces having a potential difference of \[800\,V\] are  \[0.02\,m\] apart horizontally. A particle of mass \[1.96\times {{10}^{-15}}kg\]is suspended in equilibrium between the plates. If \[e\] is the elementary charge, then charge on the particle is                                           [MP PET 1999]
  A)
                     \[e\] done clear
  B)
                                       \[3e\] done clear
  C)
                     \[6e\] done clear
  D)
                                       \[8e\] done clear
  View Solution play_arrow

• question_answer68)
  The figure shows some of the electric field lines corresponding to an electric field. The figure suggests                                                                                                                                   [MP PMT 1999]
  A)
                                                       \[{{E}_{A}}>{{E}_{B}}>{{E}_{C}}\] done clear
  B)
                                       \[{{E}_{A}}={{E}_{B}}={{E}_{C}}\] done clear
  C)
                     \[{{E}_{A}}={{E}_{C}}>{{E}_{B}}\] done clear
  D)
                                       \[{{E}_{A}}={{E}_{C}}<{{E}_{B}}\] done clear
  View Solution play_arrow

• question_answer69)
  Two spheres of radius \[a\] and \[b\] respectively are charged and joined by a wire. The ratio of electric field of the spheres is                                                                                                            [CPMT 1999; JIPMER 2000; RPET 2000]
  A)
                     \[a/b\] done clear
  B)
                                       \[b/a\] done clear
  C)
                     \[{{a}^{2}}/{{b}^{2}}\] done clear
  D)
                                       \[{{b}^{2}}/a\] done clear
  View Solution play_arrow

• question_answer70)
  A particle of mass \[m\] and charge \[q\] is placed at rest in a uniform electric field \[E\] and then released. The kinetic energy attained by the particle after moving a distance \[y\] is [CBSE PMT 1998; Kerala PMT 2005]
  A)
                     \[qE{{y}^{2}}\] done clear
  B)
                                       \[q{{E}^{2}}y\] done clear
  C)
                     \[qEy\] done clear
  D)
                                       \[{{q}^{2}}Ey\] done clear
  View Solution play_arrow

• question_answer71)
  A hollow insulated conducting sphere is given a positive charge of \[10\,\mu \,C\]. What will be the electric field at the centre of the sphere if its radius is 2 meters [CBSE PMT 1998]
  A)
                     Zero done clear
  B)
                                       \[5\,\mu \,C{{m}^{-2}}\] done clear
  C)
                     \[20\,\mu \,C{{m}^{-2}}\]                                           done clear
  D)
             \[8\,\mu \,C{{m}^{-2}}\] done clear
  View Solution play_arrow

• question_answer72)
  An electron of mass \[{{m}_{e}}\] initially at rest moves through a certain distance in a uniform electric field in time \[{{t}_{1}}\]. A proton of mass \[{{m}_{p}}\] also initially at rest takes time \[{{t}_{2}}\] to move through an equal distance in this uniform electric field. Neglecting the effect of gravity, the ratio of \[{{t}_{2}}/{{t}_{1}}\] is nearly equal to                                                                  [IIT 1997 Cancelled]
  A)
                     1 done clear
  B)
                                       \[{{({{m}_{p}}/{{m}_{e}})}^{1/2}}\] done clear
  C)
                     \[{{({{m}_{e}}/{{m}_{p}})}^{1/2}}\] done clear
  D)
                                       1836 done clear
  View Solution play_arrow

• question_answer73)
  A cube of side \[b\] has a charge \[q\] at each of its vertices. The electric field due to this charge distribution at the centre of this cube will be                                 [KCET 1994, 2000]
  A)
                     \[q/{{b}^{2}}\] done clear
  B)
                                       \[q/2{{b}^{2}}\] done clear
  C)
                     \[32q/{{b}^{2}}\] done clear
  D)
                                       Zero done clear
  View Solution play_arrow

• question_answer74)
  A charged water drop whose radius is \[0.1\,\mu m\] is in equilibrium in an electric field. If charge on it is equal to charge of an electron, then intensity of electric field will be \[(g=10\,m{{s}^{-1}})\]                                          [RPET 1997]
  A)
                     \[1.61\,N/C\]                done clear
  B)
             \[26.2\,N/C\] done clear
  C)
                     \[262\,N/C\] done clear
  D)
                                       \[1610\,N/C\] done clear
  View Solution play_arrow

• question_answer75)
  Four charges are placed on corners of a square as shown in figure having side of \[5\,cm\]. If Q is one microcoulomb, then electric field intensity at centre will be        [RPET 1999]
  A)
                     \[1.02\times {{10}^{7}}N/C\] upwards done clear
  B)
                     \[2.04\times {{10}^{7}}N/C\] downwards done clear
  C)
                     \[2.04\times {{10}^{7}}N/C\] upwards done clear
  D)
                     \[1.02\times {{10}^{7}}N/C\] downwards done clear
  View Solution play_arrow

• question_answer76)
  A sphere of radius \[1\,cm\] has potential of \[8000\,V\], then energy density near its surface will be     [RPET 1999]
  A)
             \[64\times {{10}^{5}}J/{{m}^{3}}\] done clear
  B)
                                       \[8\times {{10}^{3}}J/{{m}^{3}}\] done clear
  C)
                     \[32\,J/{{m}^{3}}\] done clear
  D)
                                       \[2.83\,J/{{m}^{3}}\] done clear
  View Solution play_arrow

• question_answer77)
  Point charges \[+4q,\,-q\] and \[+4q\] are kept on the \[x-\]axis at points \[x=0,\,x=a\] and \[x=2a\] respectively, then [CBSE PMT 1992]
  A)
                     Only \[q\] is in stable equilibrium done clear
  B)
                     None of the charges are in equilibrium done clear
  C)
                     All the charges are in unstable equilibrium done clear
  D)
                     All the charges are in stable equilibrium done clear
  View Solution play_arrow

• question_answer78)
  Two point charges of \[20\,\mu \,C\] and \[80\,\mu \,C\] are \[10\,cm\] apart. Where will the electric field strength be zero on the line joining the charges from \[20\,\mu \,C\] charge         [RPET 1997]
  A)
                     \[0.1\,m\] done clear
  B)
                                       \[0.04\,m\] done clear
  C)
                     \[0.033\,m\] done clear
  D)
                                       \[0.33\,m\] done clear
  View Solution play_arrow

• question_answer79)
  How much kinetic energy will be gained by an \[\alpha -\]particle in going from a point at \[70\,V\] to another point at \[50\,V\] [RPET 1997]
  A)
                     \[40\,eV\] done clear
  B)
                                       \[40\,keV\] done clear
  C)
                     \[40MeV\] done clear
  D)
                                       \[0\,eV\] done clear
  View Solution play_arrow

• question_answer80)
  If a charged spherical conductor of radius \[10\,cm\]has potential \[V\] at a point distant \[5\,cm\] from its centre, then the potential at a point distant \[15\,cm\] from the centre will be [SCRA 1998; JIPMER 2001, 02]
  A)
                     \[\frac{1}{3}V\] done clear
  B)
                                       \[\frac{2}{3}V\] done clear
  C)
                     \[\frac{3}{2}V\] done clear
  D)
                                       \[3V\] done clear
  View Solution play_arrow

• question_answer81)
  Two unlike charges of magnitude \[q\] are separated by a distance \[2d\]. The potential at a point midway between them is                                                                            [JIPMER 1999]
  A)
             Zero done clear
  B)
                                       \[\frac{1}{4\pi {{\varepsilon }_{0}}}\] done clear
  C)
             \[\frac{1}{4\pi {{\varepsilon }_{0}}}.\frac{q}{d}\]      done clear
  D)
             \[\frac{1}{4\pi {{\varepsilon }_{0}}}.\frac{2q}{{{d}^{2}}}\] done clear
  View Solution play_arrow

• question_answer82)
  What is the potential energy of the equal positive point charges of \[1\mu C\] each held 1 m apart in air                [AMU 1999]
  A)
             \[9\times {{10}^{-3}}J\] done clear
  B)
                                       \[9\times {{10}^{-3}}eV\] done clear
  C)
             \[2eV/m\] done clear
  D)
                                       Zero done clear
  View Solution play_arrow

• question_answer83)
  An oil drop having charge \[2e\] is kept stationary between two parallel horizontal plates 2.0 cm apart when a potential difference of 12000 volts is applied between them. If the density of oil is\[900kg/{{m}^{3}}\], the radius of the drop will be [AMU 1999]
  A)
             \[2.0\times {{10}^{-6}}m\] done clear
  B)
                                       \[1.7\times {{10}^{-6}}m\] done clear
  C)
             \[1.4\times {{10}^{-6}}m\] done clear
  D)
                                       \[1.1\times {{10}^{-6}}m\] done clear
  View Solution play_arrow

• question_answer84)
  The ratio of momenta of an electron and an a-particle which are accelerated from rest by a potential difference of 100 volt is                                                                       [UPSEAT 1999]
  A)
             1     done clear
  B)
             \[\sqrt{\frac{2{{m}_{e}}}{{{m}_{\alpha }}}}\] done clear
  C)
             \[\sqrt{\frac{{{m}_{e}}}{{{m}_{\alpha }}}}\]                done clear
  D)
             \[\sqrt{\frac{{{m}_{e}}}{2{{m}_{\alpha }}}}\] done clear
  View Solution play_arrow

• question_answer85)
  A proton is accelerated through 50,000 V. Its energy will increase by                                        [JIPMER 1999]
  A)
             5000 eV done clear
  B)
                                       \[8\times {{10}^{-15}}\]J done clear
  C)
             5000 J                                       done clear
  D)
             50,000 J done clear
  View Solution play_arrow

• question_answer86)
  When a proton is accelerated through 1V, then its kinetic energy will be                                                [CBSE PMT 1999]
  A)
             1840 eV done clear
  B)
                                       13.6 eV done clear
  C)
             1 eV done clear
  D)
             0.54 eV done clear
  View Solution play_arrow

• question_answer87)
  An electron enters between two horizontal plates separated by 2mm and having a potential difference of 1000V. The force on electron is                                                    [JIPMER 1999]
  A)
             \[8\times {{10}^{-12}}\]N done clear
  B)
                                       \[8\times {{10}^{-14}}\]N done clear
  C)
             \[8\times {{10}^{9}}\] N done clear
  D)
                                       \[8\times {{10}^{14}}\] N done clear
  View Solution play_arrow

• question_answer88)
  Two metal spheres of radii \[{{R}_{1}}\] and \[{{R}_{2}}\] are charged to the same potential. The ratio of charges on the spheres is [KCET 1999]
  A)
             \[\sqrt{{{R}_{1}}}\ :\ \sqrt{{{R}_{2}}}\] done clear
  B)
                                       \[{{R}_{1}}\ :\ {{R}_{2}}\] done clear
  C)
             \[R_{1}^{2}\ :\ R_{2}^{2}\]     done clear
  D)
             \[R_{1}^{3}:\ R_{2}^{3}\] done clear
  View Solution play_arrow

• question_answer89)
  Electric charges of \[+10\mu C,\ +5\mu C,\ -3\mu C\] and \[+8\mu C\] are placed at the corners of a square of side \[\sqrt{2}\]m. the potential at the centre of the square is [KCET (Engg./Med.) 1999]
  A)
             1.8 V                                         done clear
  B)
             \[1.8\times {{10}^{6}}\] V done clear
  C)
             \[1.8\times {{10}^{5}}\]V done clear
  D)
                                       \[1.8\times {{10}^{4}}\]V done clear
  View Solution play_arrow

• question_answer90)
  What is the magnitude of a point charge which produces an electric field of 2 N/coulomb at a distance of 60 cm (\[1/4\pi {{\varepsilon }_{0}}=9\times {{10}^{9}}N-{{m}^{2}}/{{C}^{2}}\]) [MP PET 2000; RPET 2001]
  A)
             \[8\times {{10}^{-11}}\]C done clear
  B)
                                       \[2\times {{10}^{-12}}\]C done clear
  C)
             \[3\times {{10}^{-11}}\]C done clear
  D)
                                       \[6\times {{10}^{-10}}\]C done clear
  View Solution play_arrow

• question_answer91)
  The electric field due to a charge at a distance of 3 m from it is 500 N/coulomb. The magnitude of the charge is \[\left[ \frac{1}{4\pi {{\varepsilon }_{0}}}=9\times {{10}^{9}}\frac{N-{{m}^{2}}}{coulom{{b}^{2}}} \right]\]                                               [MP PMT 2000]
  A)
             2.5 micro-coulomb             done clear
  B)
             2.0 micro-coulomb done clear
  C)
             1.0 micro-coulomb             done clear
  D)
             0.5 micro-coulomb done clear
  View Solution play_arrow

• question_answer92)
  Two charges of \[4\mu C\] each are placed at the corners A and B of an equilateral triangle of side length 0.2 m in air. The electric potential at C is \[\left[ \frac{1}{4\pi {{\varepsilon }_{0}}}=9\times {{10}^{9}}\frac{N\text{-}{{m}^{2}}}{{{C}^{2}}} \right]\] [EAMCET (Med.) 2000]
  A)
             \[9\times {{10}^{4}}\]V done clear
  B)
                                       \[18\times {{10}^{4}}\]V done clear
  C)
             \[36\times {{10}^{4}}\]V done clear
  D)
                                       \[36\times {{10}^{-4}}\]V done clear
  View Solution play_arrow

• question_answer93)
  Electric field strength due to a point charge of \[5\mu C\] at a distance of 80 cm from the charge is           [CBSE PMT 2000]
  A)
             \[8\times {{10}^{4}}\]N/C done clear
  B)
                                       \[7\times {{10}^{4}}\]N/C done clear
  C)
             \[5\times {{10}^{4}}\]N/C done clear
  D)
                                       \[4\times {{10}^{4}}\]N/C done clear
  View Solution play_arrow

• question_answer94)
  Ten electrons are equally spaced and fixed around a circle of radius R. Relative to V = 0 at infinity, the electrostatic potential V and the electric field E at the centre C are [AMU 2000]
  A)
             \[V\ne 0\] and \[\vec{E}\ne 0\] done clear
  B)
                                       \[V\ne 0\] and \[\vec{E}=0\] done clear
  C)
             \[V=0\] and \[\vec{E}=0\]       done clear
  D)
             \[V=0\] and \[\vec{E}\ne 0\] done clear
  View Solution play_arrow

• question_answer95)
  Two positive point charges of \[12\mu C\] and \[8\mu C\] are 10cm apart. The work done in bringing them 4 cm closer is [AMU 2000]
  A)
             5.8 J                                          done clear
  B)
             5.8 eV done clear
  C)
             13 J done clear
  D)
             13 eV done clear
  View Solution play_arrow

• question_answer96)
  Three identical point charges, as shown are placed at the vertices of an isosceles right angled triangle. Which of the numbered vectors coincides in direction with the electric field at the mid-point M of the hypotenuse                                                                                                            [AMU 2000]
  A)
             1     done clear
  B)
             2 done clear
  C)
             3     done clear
  D)
             4 done clear
  View Solution play_arrow

• question_answer97)
  The displacement of a charge Q in the electric field \[E={{e}_{1}}\hat{i}+{{e}_{2}}\hat{j}+{{e}_{3}}\hat{k}\] is \[\hat{r}=a\hat{i}+b\hat{j}\]. The work done is                                                                                [EAMCET (Engg.) 2000]
  A)
             \[Q(a{{e}_{1}}+b{{e}_{2}})\] done clear
  B)
                                       \[Q\sqrt{{{\left( a{{e}_{1}} \right)}^{2}}+{{\left( b{{e}_{2}} \right)}^{2}}}\] done clear
  C)
             \[Q({{e}_{1}}+{{e}_{2}})\sqrt{{{a}^{2}}+{{b}^{2}}}\] done clear
  D)
                                       \[Q(\sqrt{e_{1}^{2}+e_{2}^{2})}\ (a+b)\] done clear
  View Solution play_arrow

• question_answer98)
  The potential at a point, due to a positive charge of \[100\mu C\] at a distance of 9m, is                                                 [KCET (Med.) 2000]
  A)
             \[{{10}^{4}}\]V                     done clear
  B)
             \[{{10}^{5}}\]V done clear
  C)
             \[{{10}^{6}}\]V                     done clear
  D)
             \[{{10}^{7}}\]V done clear
  View Solution play_arrow

• question_answer99)
  There is a solid sphere of radius ?R? having uniformly distributed charge. What is the relation between electric field ?E? (inside the sphere) and radius of sphere ?R? is [Pb. PMT 2000]
  A)
             \[E\propto {{R}^{-2}}\] done clear
  B)
                                       \[E\propto {{R}^{-1}}\] done clear
  C)
             \[E\propto \frac{1}{{{R}^{3}}}\] done clear
  D)
                                       \[E\propto {{R}^{2}}\] done clear
  View Solution play_arrow

• question_answer100)
  Two charges \[+5\mu C\] and \[+10\mu C\] are placed 20 cm apart. The net electric field at the mid-Point between the two charges is                                               [KCET (Med.) 2000]
  A)
             \[4.5\times {{10}^{6}}\] N/C directed towards \[+5\mu C\] done clear
  B)
             \[4.5\times {{10}^{6}}\] N/C directed towards \[+10\mu C\] done clear
  C)
             \[13.5\times {{10}^{6}}\] N/C directed towards \[+5\mu C\] done clear
  D)
             \[13.5\times {{10}^{6}}\] N/C directed towards \[+10\mu C\] done clear
  View Solution play_arrow

• question_answer101)
  Which of the following is deflected by electric field                                                                                              [CPMT 2000]
  A)
             X-rays                                      done clear
  B)
             \[\gamma \]-rays done clear
  C)
             Neutrons done clear
  D)
                                       \[\alpha \]-particles done clear
  View Solution play_arrow

• question_answer102)
  As shown in the figure, charges \[+q\] and \[-q\] are placed at the vertices \[B\] and \[C\] of an isosceles triangle. The potential at the vertex A is                                     [MP PET 2000]
  A)
             \[\frac{1}{4\pi {{\varepsilon }_{0}}}.\frac{2q}{\sqrt{{{a}^{2}}+{{b}^{2}}}}\] done clear
  B)
             Zero done clear
  C)
             \[\frac{1}{4\pi {{\varepsilon }_{0}}}.\frac{q}{\sqrt{{{a}^{2}}+{{b}^{2}}}}\] done clear
  D)
             \[\frac{1}{4\pi {{\varepsilon }_{0}}}.\frac{(-q)}{\sqrt{{{a}^{2}}+{{b}^{2}}}}\] done clear
  View Solution play_arrow

• question_answer103)
  Consider the points lying on a straight line joining two fixed opposite charges. Between the charges there is                                                                                          [Roorkee 2000]
  A)
             No point where electric field is zero done clear
  B)
             Only one point where electric field is zero done clear
  C)
             No point where potential is zero done clear
  D)
             Only one point where potential is zero done clear
  View Solution play_arrow

• question_answer104)
  A charged particle of mass \[5\times {{10}^{-5}}kg\] is held stationary in space by placing it in an electric field of strength \[{{10}^{7}}N{{C}^{-1}}\] directed vertically downwards. The charge on the particle is [EAMCET 2000]
  A)
             \[-20\times {{10}^{-5}}\mu C\] done clear
  B)
                                       \[-5\times {{10}^{-5}}\mu C\] done clear
  C)
             \[5\times {{10}^{-5}}\mu C\] done clear
  D)
                                       \[20\times {{10}^{-5}}\mu C\] done clear
  View Solution play_arrow

• question_answer105)
  Three charges \[Q,\,+q\] and \[+q\] are placed at the vertices of a right-angled isosceles triangle as shown. The net electrostatic energy of the configuration is zero if Q is equal to                                                                                                                                                                              [IIT-JEE (Screening) 2000]
  A)
             \[\frac{-q}{1+\sqrt{2}}\] done clear
  B)
             \[\frac{-2q}{2+\sqrt{2}}\] done clear
  C)
             \[-2q\] done clear
  D)
             \[+q\] done clear
  View Solution play_arrow

• question_answer106)
  Two electric charges \[12\mu C\] and \[-6\mu C\] are placed 20 cm apart in air. There will be a point P on the line joining these charges and outside the region between them, at which the electric potential is zero. The distance of P from \[-6\mu C\] charge is                                                     [EAMCET 2000]
  A)
             0.10 m                                      done clear
  B)
             0.15 m done clear
  C)
             0.20 m done clear
  D)
             0.25 m done clear
  View Solution play_arrow

• question_answer107)
  In the given figure distance of the point from A where the electric field is zero is                                                                       [RPMT 2000]
  A)
             20 cm                                       done clear
  B)
             10 cm done clear
  C)
             33 cm done clear
  D)
             None of these done clear
  View Solution play_arrow

• question_answer108)
  Figures below show regular hexagons, with charges at the vertices. In which of the following cases the electric field at the centre is not zero                                                   [AMU 2000]           
  A)
             1     done clear
  B)
             2 done clear
  C)
             3     done clear
  D)
             4 done clear
  View Solution play_arrow

• question_answer109)
  An electron is moving towards x-axis. An electric field is along y-direction then path of electron is             [RPET 2000]
  A)
             Circular done clear
  B)
                                       Elliptical done clear
  C)
             Parabola done clear
  D)
                                       None of these done clear
  View Solution play_arrow

• question_answer110)
  An electron enters in an electric field with its velocity in the direction of the electric lines of force. Then                 [MP PMT 2000]
  A)
             The path of the electron will be a circle done clear
  B)
             The path of the electron will be a parabola done clear
  C)
             The velocity of the electron will decrease done clear
  D)
             The velocity of the electron will increase done clear
  View Solution play_arrow

• question_answer111)
  An electron of mass \[m\] and charge \[e\] is accelerated from rest through a potential difference V in vacuum. The final speed of the electron will be                                              [MP PMT 2000; AMU (Engg.) 2000]
  A)
             \[V\sqrt{e/m}\] done clear
  B)
                                       \[\sqrt{eV/m}\] done clear
  C)
             \[\sqrt{2eV/m}\] done clear
  D)
                                       \[2eV/m\] done clear
  View Solution play_arrow

• question_answer112)
  The radius of a soap bubble whose potential is 16V is doubled. The new potential of the bubble will be                                                                                          [Pb. PMT 2000]
  A)
             2V  done clear
  B)
             4V done clear
  C)
             8V done clear
  D)
             16V done clear
  View Solution play_arrow

• question_answer113)
  The dimension of (1/2) \[{{\varepsilon }_{0}}{{E}^{2}}({{\varepsilon }_{0}}\]: permittivity of free space; \[E\]: electric field) is    [IIT-JEE (Screening) 2000; KCET 2000]
  A)
             \[ML{{T}^{^{-1}}}\]            done clear
  B)
             \[M{{L}^{2}}{{T}^{-2}}\] done clear
  C)
             \[M{{L}^{-1}}{{T}^{-2}}\] done clear
  D)
                                       \[M{{L}^{2}}{{T}^{-1}}\] done clear
  View Solution play_arrow

• question_answer114)
  In the rectangle, shown below, the two corners have charges \[{{q}_{1}}=-5\mu C\] and \[{{q}_{2}}=+2.0\mu C\]. The work done in moving a charge \[+3.0\mu C\] from \[B\] to \[A\] is (take \[1/4\pi {{\varepsilon }_{0}}={{10}^{10}}N\text{-}{{m}^{2}}/{{C}^{2}}\])                                             [AMU 2001]
  A)
             2.8 J done clear
  B)
                                       3.5 J done clear
  C)
             4.5 J                                          done clear
  D)
             5.5 J done clear
  View Solution play_arrow

• question_answer115)
  A cube of a metal is given a positive charge Q. For the above system, which of the following statements is true [MP PET 2001]
  A)
             Electric potential at the surface of the cube is zero done clear
  B)
             Electric potential within the cube is zero done clear
  C)
             Electric field is normal to the surface of the cube done clear
  D)
             Electric field varies within the cube done clear
  View Solution play_arrow

• question_answer116)
  If \[q\] is the charge per unit area on the surface of a conductor, then the electric field intensity at a point on the surface is                                                 [MP PET 2001; UPSEAT 2001]
  A)

  (1)

             \[\left( \frac{q}{{{\varepsilon }_{0}}} \right)\] normal to surface done clear
  B)
             \[\left( \frac{q}{2{{\varepsilon }_{0}}} \right)\] normal to surface done clear
  C)
             \[\left( \frac{q}{{{\varepsilon }_{0}}} \right)\]  tangential to surface done clear
  D)
             \[\left( \frac{q}{2{{\varepsilon }_{0}}} \right)\]  tangential to surface done clear
  View Solution play_arrow

• question_answer117)
  A hollow conducting sphere of radius \[R\] has a charge \[(+Q)\] on its surface. What is the electric potential within the sphere at a distance \[r=\frac{R}{3}\] from its centre              [MP PMT 2001; UPSEAT 2001; MP PET 2001, 02; Orissa JEE 2005]
  A)
             Zero                                          done clear
  B)
             \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{Q}{r}\] done clear
  C)
             \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{Q}{R}\] done clear
  D)
                                       \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{Q}{{{r}^{2}}}\] done clear
  View Solution play_arrow

• question_answer118)
  A spherical conductor of radius 2m is charged to a potential of 120 V. It is now placed inside another hollow spherical conductor of radius 6m. Calculate the potential to which the bigger sphere would be raised                         [KCET 2001]
  A)
             20 V                                          done clear
  B)
             60 V done clear
  C)
             80 V                                          done clear
  D)
             40 V done clear
  View Solution play_arrow

• question_answer119)
  A charge \[(-q)\] and another charge \[(+Q)\] are kept at two points A and B respectively. Keeping the charge \[(+Q)\] fixed at B, the charge \[(-q)\] at A is moved to another point C such that ABC forms an equilateral triangle of side l. The net work done in moving the charge \[(-q)\] is [MP PET 2001]
  A)
             \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{Qq}{l}\] done clear
  B)
                                       \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{Qq}{{{l}^{2}}}\] done clear
  C)
             \[\frac{1}{4\pi {{\varepsilon }_{0}}}Qql\] done clear
  D)
                                       Zero done clear
  View Solution play_arrow

• question_answer120)
  A particle of mass ?m? and charge ?q? is accelerated through a potential difference of V volt, its energy will be [MP PET 2001]
  A)
             \[qV\]                                      done clear
  B)
             \[mqV\] done clear
  C)
             \[\left( \frac{q}{m} \right)V\] done clear
  D)
                     \[\frac{q}{mV}\] done clear
  View Solution play_arrow

• question_answer121)
  Two spheres A and B of radius ?a? and ?b? respectively are at same electric potential. The ratio of the surface charge densities of A and B is                                             [MP PMT 2001]
  A)
             \[\frac{a}{b}\]                      done clear
  B)
             \[\frac{b}{a}\] done clear
  C)
             \[\frac{{{a}^{2}}}{{{b}^{2}}}\]                                            done clear
  D)
             \[\frac{{{b}^{2}}}{{{a}^{2}}}\] done clear
  View Solution play_arrow

• question_answer122)
  Potential at a point x-distance from the centre inside the conducting sphere of radius R and charged with charge Q is                    [MP PMT 2001]
  A)
             \[\frac{Q}{R}\]                     done clear
  B)
             \[\frac{Q}{x}\] done clear
  C)
             \[\frac{Q}{{{x}^{2}}}\]       done clear
  D)
             \[xQ\] done clear
  View Solution play_arrow

• question_answer123)
  Electric field intensity at a point in between two parallel sheets with like charges of same surface charge densities \[(\sigma )\] is [MP PMT 2001]
  A)
             \[\frac{\sigma }{2{{\varepsilon }_{0}}}\]                       done clear
  B)
             \[\frac{\sigma }{{{\varepsilon }_{0}}}\] done clear
  C)
             Zero                                          done clear
  D)
             \[\frac{2\sigma }{{{\varepsilon }_{0}}}\] done clear
  View Solution play_arrow

• question_answer124)
  In an hydrogen atom, the electron revolves around the nucleus in an orbit of radius \[0.53\times {{10}^{-10}}m\]. Then the electrical potential produced by the nucleus at the position of the electron is                                              [Pb. PMT 2001]
  A)
             ? 13.6 V done clear
  B)
                                       ? 27.2 V done clear
  C)
             27.2 V                                       done clear
  D)
             13.6 V done clear
  View Solution play_arrow

• question_answer125)
  Consider two point charges of equal magnitude and opposite sign separated by a certain distance. The neutral point due to them                                                        [Kerala (Engg.) 2001]
  A)
             Does not exist done clear
  B)
             Will be in mid-way between them done clear
  C)
             Lies on the perpendicular bisector of the line joining the two done clear
  D)
             Will be closer to the negative charge done clear
  View Solution play_arrow

• question_answer126)
  Two small spherical balls each carrying a charge \[Q=10\mu C\] (10 micro-coulomb) are suspended by two insulating threads of equal lengths 1m each, from a point fixed in the ceiling. It is found that in equilibrium threads are separated by an angle \[{{60}^{o}}\] between them, as shown in the figure. What is the tension in the threads (Given: \[\frac{1}{(4\pi {{\varepsilon }_{0}})}=9\times {{10}^{9}}Nm/{{C}^{2}}\])               [MP PET 2001; Pb PET 2003]
  A)
             18 N done clear
  B)
             1.8 N done clear
  C)
             0.18 N done clear
  D)
             None of the above done clear
  View Solution play_arrow

• question_answer127)
  A ball of mass 1 g and charge \[{{10}^{-8}}C\] moves from a point A. where potential is 600 volt to the point B where potential is zero. Velocity of the ball at the point B is 20 cm/s. The velocity of the ball at the point A will be            [KCET 2001]
  A)
             22.8 cm/s done clear
  B)
                                       228 cm/s done clear
  C)
             16.8 m/s                                  done clear
  D)
             168 m/s done clear
  View Solution play_arrow

• question_answer128)
  The acceleration of an electron in an electric field of magnitude 50 V/cm, if e/m value of the electron is \[1.76\times {{10}^{11}}\]C/kg, is                                                     [CPMT 2001]
  A)
             \[8.8\times {{10}^{14}}\]m/sec2 done clear
  B)
             \[6.2\times {{10}^{13}}\] m/sec2 done clear
  C)
             \[5.4\times {{10}^{12}}\] m/sec2                                      done clear
  D)
             Zero done clear
  View Solution play_arrow

• question_answer129)
  Three charges \[Q,(+q)\] and \[(+q)\] are placed at the vertices of an equilateral triangle of side l as shown in the figure. If the net electrostatic energy of the system is zero, then Q is equal to                                                    [MP PET 2001]
  A)
             \[\left( -\frac{q}{2} \right)\] done clear
  B)
             \[(-q)\] done clear
  C)
             \[(+q)\] done clear
  D)
             Zero done clear
  View Solution play_arrow

• question_answer130)
  A positively charged particle moving along x-axis with a certain velocity enters a uniform electric field directed along positive y-axis. Its                                               [AMU (Engg.) 2001]
  A)
             Vertical velocity changes but horizontal velocity remains constant done clear
  B)
             Horizontal velocity changes but vertical velocity remains constant done clear
  C)
             Both vertical and horizontal velocities change done clear
  D)
             Neither vertical nor horizontal velocity changes done clear
  View Solution play_arrow

• question_answer131)
  Electric potential at any point is \[V=-5x+3y+\sqrt{15}z\], then the magnitude of the electric field is         [MP PET 2002]
  A)
             \[3\sqrt{2}\]                          done clear
  B)
             \[4\sqrt{2}\] done clear
  C)
             \[5\sqrt{2}\]                          done clear
  D)
             7 done clear
  View Solution play_arrow

• question_answer132)
  The work done in bringing a 20 coulomb charge from point A to point B for distance 0.2m is 2J. The potential difference between the two points will be (in volt) [RPET 1999; MP PMT 2002; AIEEE 2002]
  A)
             0.2  done clear
  B)
             8 done clear
  C)
             0.1  done clear
  D)
             0.4 done clear
  View Solution play_arrow

• question_answer133)
  A hollow sphere of charge does not produce an electric field at any         [MNR 1985; RPET 2001; DPMT 2002; Kerala PMT 2004; Pb PET 2004; Orissa PMT 2004]
  A)
             Point beyond 2 metres     done clear
  B)
             Point beyond 10 metres done clear
  C)
             Interior point done clear
  D)
             Outer point done clear
  View Solution play_arrow

• question_answer134)
  If \[4\times {{10}^{20}}eV\] energy is required to move a charge of 0.25 coulomb between two points. Then what will be the potential difference between them                                        [MHCET 2002]
  A)
             178 V                                        done clear
  B)
             256 V done clear
  C)
             356 V                                        done clear
  D)
             None of these done clear
  View Solution play_arrow

• question_answer135)
  Kinetic energy of an electron accelerated in a potential difference of 100 V is      [AFMC 1999; MP PMT 2002]
  A)
                                              \[1.6\times {{10}^{-17}}\]J done clear
  B)
                                                           \[1.6\times {{10}^{21}}\]J done clear
  C)
             \[1.6\times {{10}^{-29}}\]J      done clear
  D)
             \[1.6\times {{10}^{-34}}\]J                                done clear
  View Solution play_arrow

• question_answer136)
  A drop of \[{{10}^{-6}}kg\] water carries \[{{10}^{-6}}C\] charge. What electric field should be applied to balance its weight (assume \[g=10m/{{s}^{2}})\]                                                                     [MP PET 2002]
  A)
             10 V/m upward                    done clear
  B)
             10 V/m downward done clear
  C)
             0.1 V/m downward            done clear
  D)
             0.1 V/m upward done clear
  View Solution play_arrow

• question_answer137)
  A charged particle of mass 0.003 gm is held stationary in space by placing it in a downward direction of electric field of \[6\times {{10}^{4}}N/C\]. Then the magnitude of the charge is [Orissa JEE 2002]
  A)
             \[5\times {{10}^{-4}}C\] done clear
  B)
                                       \[5\times {{10}^{-10}}C\] done clear
  C)
             \[-18\times {{10}^{-6}}C\] done clear
  D)
                                       \[-5\times {{10}^{-9}}C\] done clear
  View Solution play_arrow

• question_answer138)
  Two point charges \[+9e\] and \[+e\] are at 16 cm away from each other. Where should another charge q be placed between them so that the system remains in equilibrium [MP PET 2002]
  A)
             24 cm from \[+9e\]            done clear
  B)
             12 cm from \[+9e\] done clear
  C)
             24 cm from \[+e\]               done clear
  D)
             12 cm from \[+e\] done clear
  View Solution play_arrow

• question_answer139)
  If 3 charges are placed at the vertices of equilateral triangle of charge ?q? each. What is the net potential energy, if the side of equilateral \[\Delta \] is l cm                                                                         [AIEEE 2002]
  A)
             \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{{{q}^{2}}}{l}\] done clear
  B)
                                       \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{2{{q}^{2}}}{l}\] done clear
  C)
             \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{3{{q}^{2}}}{l}\] done clear
  D)
                                       \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{4{{q}^{2}}}{l}\] done clear
  View Solution play_arrow

• question_answer140)
  The distance between charges \[5\times {{10}^{-11}}C\] and \[-2.7\times {{10}^{-11}}C\] is 0.2 m. The distance at which a third charge should be placed in order that it will not experience any force along the line joining the two charges is [Kerala PET 2002]
  A)
             0.44 m                                      done clear
  B)
             0.65 m done clear
  C)
             0.556 m                                   done clear
  D)
             0.350 m done clear
  View Solution play_arrow

• question_answer141)
  If identical charges \[(-q)\] are placed at each corner of a cube of side b, then electric potential energy of charge \[(+q)\] which is placed at centre of the cube will be [CBSE PMT 2002]
  A)
             \[\frac{8\sqrt{2}{{q}^{2}}}{4\pi {{\varepsilon }_{0}}b}\]       done clear
  B)
             \[\frac{-8\sqrt{2}{{q}^{2}}}{\pi {{\varepsilon }_{0}}b}\] done clear
  C)
             \[\frac{-4\sqrt{2}{{q}^{2}}}{\pi {{\varepsilon }_{0}}b}\] done clear
  D)
                                       \[\frac{-4{{q}^{2}}}{\sqrt{3}\pi {{\varepsilon }_{0}}b}\] done clear
  View Solution play_arrow

• question_answer142)
  An electron having charge ?e? and mass ?m? is moving in a uniform electric field E. Its acceleration will be [AIIMS 2002]
  A)
             \[\frac{{{e}^{2}}}{m}\]      done clear
  B)
             \[\frac{{{E}^{2}}e}{m}\] done clear
  C)
             \[\frac{eE}{m}\]                  done clear
  D)
             \[\frac{mE}{e}\] done clear
  View Solution play_arrow

• question_answer143)
  Cathode rays travelling from east to west enter into region of electric field directed towards north to south in the plane of paper. The deflection of cathode rays is towards [CPMT 2002]
  A)
             East                                           done clear
  B)
             South done clear
  C)
             West                                        done clear
  D)
             North done clear
  View Solution play_arrow

• question_answer144)
  An \[\alpha \]-particle is accelerated through a potential difference of 200V. The increase in its kinetic energy is                                                                                            [UPSEAT 2002]
  A)
             100 eV                                      done clear
  B)
             200 eV done clear
  C)
             400 eV done clear
  D)
             800 eV done clear
  View Solution play_arrow

• question_answer145)
  A simple pendulum of period \[T\] has a metal bob which is negatively charged. If it is allowed to oscillate above a positively charged metal plate, its period will                                                                     [AIEEE 2002; CBSE PMT 2001]
  A)
             Remains equal to T             done clear
  B)
             Less than \[T\] done clear
  C)
             Greater than \[T\] done clear
  D)
                                       Infinite done clear
  View Solution play_arrow

• question_answer146)
  A charged particle of mass \[m\] and charge \[q\] is released from rest in a uniform electric field \[E.\] Neglecting the effect of gravity, the kinetic energy of the charged particle after ?t? second is                                      [KCET 2003]
  A)
             \[\frac{E{{q}^{2}}m}{2{{t}^{2}}}\]                                    done clear
  B)
             \[\frac{2{{E}^{2}}{{t}^{2}}}{mq}\] done clear
  C)
             \[\frac{{{E}^{2}}{{q}^{2}}{{t}^{2}}}{2m}\] done clear
  D)
                                       \[\frac{Eqm}{t}\] done clear
  View Solution play_arrow

• question_answer147)
  A proton is about 1840 times heavier than an electron. When it is accelerated by a potential difference of 1 kV, its kinetic energy will be                                 [AIIMS 2003; DCE 2001]
  A)
             1840 keV done clear
  B)
                                       1/1840 keV done clear
  C)
             1 keV                                        done clear
  D)
             920 keV done clear
  View Solution play_arrow

• question_answer148)
  A conducting sphere of radius \[R=20\]cm is given a charge \[Q=16\mu C\]. What is \[\overrightarrow{E}\] at centre                                                              [BHU 2003]
  A)
             \[3.6\times {{10}^{6}}N/C\] done clear
  B)
                                       \[1.8\times {{10}^{6}}N/C\] done clear
  C)
             Zero                                          done clear
  D)
             \[0.9\times {{10}^{6}}N/C\] done clear
  View Solution play_arrow

• question_answer149)
  A thin spherical conducting shell of radius \[R\] has a charge q. Another charge Q is placed at the centre of the shell. The electrostatic potential at a point p a distance \[\frac{R}{2}\] from the centre of the shell is                                   [AIEEE 2003]
  A)
             \[\frac{(q+Q)}{4\pi {{\varepsilon }_{0}}}\frac{2}{R}\] done clear
  B)
                                       \[\frac{2Q}{4\pi {{\varepsilon }_{0}}R}\] done clear
  C)
             \[\frac{2Q}{4\pi {{\varepsilon }_{0}}R}-\frac{2q}{4\pi {{\varepsilon }_{0}}R}\]           done clear
  D)
             \[\frac{2Q}{4\pi {{\varepsilon }_{0}}R}+\frac{q}{4\pi {{\varepsilon }_{0}}R}\] done clear
  View Solution play_arrow

• question_answer150)
  A hollow conducting sphere is placed in an electric field produced by a point charge placed at P as shown in figure. Let \[{{V}_{A}},{{V}_{B}},{{V}_{C}}\] be the potentials at points \[A,B\] and C respectively. Then      [Orissa JEE 2003]
  A)
                                              \[{{V}_{C}}>{{V}_{B}}\] done clear
  B)
                                       \[{{V}_{B}}>{{V}_{C}}\] done clear
  C)
             \[{{V}_{A}}>{{V}_{B}}\] done clear
  D)
                                       \[{{V}_{A}}={{V}_{C}}\] done clear
  View Solution play_arrow

• question_answer151)
  A point charge is kept at the centre of a metallic insulated spherical shell. Then                                  [Orissa JEE 2003]
  A)
             Electric field out side the sphere is zero done clear
  B)
             Electric field inside the sphere is zero done clear
  C)
             Net induced charge on the sphere is zero done clear
  D)
             Electric potential inside the sphere is zero done clear
  View Solution play_arrow

• question_answer152)
  An electron moving with the speed \[5\times {{10}^{6}}\] per sec is shooted parallel to the electric field of intensity \[1\times {{10}^{3}}N/C\]. Field is responsible for the retardation of motion of electron. Now evaluate the distance travelled by the electron before coming to rest for an instant (mass of \[e=9\times {{10}^{-31}}Kg.\] charge \[=1.6\times {{10}^{-19}}C)\]                               [MP PMT 2003]
  A)
             7 m                                            done clear
  B)
             0.7 mm done clear
  C)
             7 cm done clear
  D)
             0.7 cm done clear
  View Solution play_arrow

• question_answer153)
  An electron enters in high potential region \[{{V}_{2}}\] from lower potential region \[{{V}_{1}}\] then its velocity                    [MP PMT 2003]
  A)
             Will increase done clear
  B)
             Will change in direction but not in magnitude done clear
  C)
             No change in direction of field done clear
  D)
             No change in direction perpendicular to field done clear
  View Solution play_arrow

• question_answer154)
  The electric potential at the surface of an atomic nucleus (Z = 50) of radius \[9.0\times ~{{10}^{-13}}cm\]is                              [CPMT 1990; Pb. PMT 2002; BVP 2003; MP PET 2004]
  A)
             80 volts done clear
  B)
                                       \[8\times {{10}^{6}}\]volts done clear
  C)
             9 volts                                      done clear
  D)
             \[9\times {{10}^{5}}\]volts done clear
  View Solution play_arrow

• question_answer155)
  A pellet carrying charge of 0.5 coulombs is accelerated through a potential of 2,000 volts. It attains  a kinetic energy equal to  [NCERT 1973; CPMT 1973; JIPMER 2002]
  A)
             1000 ergs done clear
  B)
                                       1000 joules done clear
  C)
             1000 kWh done clear
  D)
                                       500 ergs done clear
  View Solution play_arrow

• question_answer156)
  A particle has a mass 400 times than that of the electron and charge is double than that of a electron. It is accelerated by 5V of potential difference. Initially the particle was at rest, then its final kinetic energy will be [MP PMT 1990; DPMT 1999]
  A)
             5 eV                                          done clear
  B)
             10 eV done clear
  C)
             100 eV done clear
  D)
                                       2000 eV done clear
  View Solution play_arrow

• question_answer157)
  An electron (charge = \[1.6\times {{10}^{-19}}\] coulomb) is accelerated through a potential of 1,00,000 volts. The energy required by the electron is                                                                           [MP PET 1989]
  A)
             \[1.6\times {{10}^{-24}}\] joule                                        done clear
  B)
             \[1.6\times {{10}^{-14}}\,\,erg\] done clear
  C)
             \[0.53\times {{10}^{-14}}\]joule                                       done clear
  D)
             \[1.6\times {{10}^{-14}}\] joule done clear
  View Solution play_arrow

• question_answer158)
  The charge given to a hollow sphere of radius 10 cm is \[3.2\times {{10}^{19}}\]coulomb. At a distance of 4 cm from its centre, the electric potential will be                                                                        [MP PMT 1990]
  A)
             \[28.8\times {{10}^{-9}}\,volts\] done clear
  B)
             \[288\,volts\] done clear
  C)
             2.88 volts done clear
  D)
                                       Zero done clear
  View Solution play_arrow

• question_answer159)
  Work done in moving a positive charge on an equipotential surface is                                     [BCECE 2004]
  A)
             Finite, positive but not zero done clear
  B)
             Finite, negative but not zero done clear
  C)
             Zero done clear
  D)
             Infinite done clear
  View Solution play_arrow

• question_answer160)
  A charge of 10 e.s.u. is placed at a distance of 2 cm from a charge of 40 e.s.u. and 4 cm from another charge of 20 e.s.u. The potential energy of the charge 10 e.s.u. is (in ergs) [CPMT 1976; MP PET 1989]
  A)
             87.5                                           done clear
  B)
             112.5 done clear
  C)
             150 done clear
  D)
             250 done clear
  View Solution play_arrow

• question_answer161)
  A table tennis ball which has been covered with conducting paint is suspended by a silk thread so that it hang between two plates, out of which one is earthed and other is connected to a high voltage generator. This ball
  A)
             Is attracted towards high voltage plate and stays there done clear
  B)
             Hangs without moving done clear
  C)
             Swing backward and forward hitting each plate in turn done clear
  D)
             Is attracted to earthed plate and stays there done clear
  View Solution play_arrow

• question_answer162)
  A sphere of 4 cm radius is suspended within a hollow sphere of 6 cm radius. The inner sphere is charged to potential 3 e.s.u. and the outer sphere is earthed. The charge on the inner sphere is                                          [MP PMT 1991]
  A)
             54 e.s.u. done clear
  B)
                                       \[\frac{1}{4}\] e.s.u. done clear
  C)
             30 e.s.u. done clear
  D)
                                       36 e.s.u. done clear
  View Solution play_arrow

• question_answer163)
  State which of the following is correct           [CPMT 1974, 80]
  A)
             Joule = coulomb × volt      done clear
  B)
             Joule = coulomb/volt done clear
  C)
                     Joule = volt × ampere done clear
  D)
             Joule = volt/ampere done clear
  View Solution play_arrow

• question_answer164)
  When a positive q charge is taken from lower potential to a higher potential point, then its potential energy will
  A)
                     Decrease                        done clear
  B)
             Increases done clear
  C)
                     Remain unchanged    done clear
  D)
             Become zero done clear
  View Solution play_arrow

• question_answer165)
  When a negative charge is taken at a height from earth's surface, then its potential energy                          [DPMT 2002]
  A)
                     Decreases                      done clear
  B)
             Increases done clear
  C)
                     Remains unchanged  done clear
  D)
             Will become infinity done clear
  View Solution play_arrow

• question_answer166)
  When a charge of 3 coulombs is placed in a uniform electric field, it experiences a force of 3000 Newton. Within this field, potential difference between two points separated by a distance of 1 cm is             [MP PMT 1986; 2000]
  A)
             10 volts done clear
  B)
                                       90 volts done clear
  C)
                     1000 volts                       done clear
  D)
             3000 volts done clear
  View Solution play_arrow

• question_answer167)
  There are two equipotential surface as shown in figure. The distance between them is r. The charge of ?q coulomb is taken from the surface A to B, the resultant work done will be                   [MP PMT 1986; CPMT 1986, 88]
  A)
                     \[W=\frac{1}{4\pi {{\varepsilon }_{o}}}\frac{q}{r}\] done clear
  B)
                     \[W=\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{q}{{{r}^{2}}}\] done clear
  C)
                     \[W=-\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{q}{{{r}^{2}}}\] done clear
  D)
                     W = zero done clear
  View Solution play_arrow

• question_answer168)
  When one electron is taken towards the other electron, then the electric potential energy of the system             [RPET 1999;          CBSE PMT 1993, 99; Pb. PMT 1999; BHU 2000, 02]
  A)
                     Decreases                      done clear
  B)
             Increases done clear
  C)
                     Remains unchanged  done clear
  D)
             Becomes zero done clear
  View Solution play_arrow

• question_answer169)
  A hollow metal sphere of radius 5cm is charged such that the potential on its surface is 10V. The potential at a distance of 2cm from the centre of the sphere             [MP PET 1992; MP PMT 1996]
  A)
                     Zero done clear
  B)
                                       10 V done clear
  C)
                     4 V done clear
  D)
                                       10/3 V done clear
  View Solution play_arrow

• question_answer170)
  The work done in carrying a charge of \[5\mu \,C\] from a point A to a point B in an electric field is 10mJ.  The potential difference \[({{V}_{B}}-{{V}_{A}})\] is then [Haryana CEE 1996]
  A)
             + 2kV done clear
  B)
             ? 2 kV done clear
  C)
                     + 200 V done clear
  D)
                                       ? 200 V done clear
  View Solution play_arrow

• question_answer171)
  Value of potential at a point due to a point charge is  [MP PET 1996]
  A)
             Inversely proportional to square of the distance done clear
  B)
             Directly proportional to square of the distance done clear
  C)
             Inversely proportional to the distance done clear
  D)
             Directly proportional to the distance done clear
  View Solution play_arrow

• question_answer172)
  Electric potential of earth is taken to be zero because earth is a good      [AIIMS 1998; BHU 2002]
  A)
                     Insulator done clear
  B)
                                       Conductor done clear
  C)
                     Semiconductor                 done clear
  D)
             Dielectric done clear
  View Solution play_arrow

• question_answer173)
  There is 10 units of charge at the centre of a circle of radius 10m. The work done in moving 1 unit of charge around the circle once is [EAMCET (Med.) 1995; AIIMS 2000; Pb. PMT 2000]
  A)
             Zero done clear
  B)
                                       10 units done clear
  C)
             100 units done clear
  D)
                                       1 unit done clear
  View Solution play_arrow

• question_answer174)
  Two parallel plates separated by a distance of \[5mm\] are kept at a potential difference of \[50\,V.\] A particle  of mass \[{{10}^{-15}}kg\] and charge \[{{10}^{-11}}C\] enters in it with a velocity \[{{10}^{7}}m/s.\] The acceleration of the particle will be  [MP PMT 1997]
  A)
             \[{{10}^{8}}m/{{s}^{2}}\] done clear
  B)
                                       \[5\times {{10}^{5}}m/{{s}^{2}}\] done clear
  C)
             \[{{10}^{5}}m/{{s}^{2}}\] done clear
  D)
                                       \[2\times {{10}^{3}}m/{{s}^{2}}\] done clear
  View Solution play_arrow

• question_answer175)
  Three point charges are placed at the corners of an equilateral triangle. Assuming only electrostatic forces are acting                                                                      [KCET 2002]
  A)
             The system can never be in equilibrium done clear
  B)
                     The system will be in equilibrium if the charges rotate about the centre of the triangle done clear
  C)
             The system will be in equilibrium if the charges have different magnitudes and different signs done clear
  D)
             The system will be in equilibrium if the charges have the same magnitudes but different signs done clear
  View Solution play_arrow

• question_answer176)
  If an insulated non-conducting sphere of radius R has charge density \[\rho \]. The electric field at a distance \[r\] from the centre of sphere \[(r<R)\] will be                                                     [BHU 2003]
  A)
             \[\frac{\rho \,R}{3{{\varepsilon }_{0}}}\]                      done clear
  B)
             \[\frac{\rho \,r}{{{\varepsilon }_{0}}}\]   done clear
  C)
             \[\frac{\rho \,r}{3{{\varepsilon }_{0}}}\] done clear
  D)
             \[\frac{3\rho \,R}{{{\varepsilon }_{0}}}\] done clear
  View Solution play_arrow

• question_answer177)
  Two plates are at potentials ?10 V and +30 V. If the separation between the plates be 2 cm. The electric field between them is                                                       [Pb. PET 2000]
  A)
             2000 V/m done clear
  B)
             1000 V/m done clear
  C)
                     500 V/m done clear
  D)
                                      3000 V/m done clear
  View Solution play_arrow

• question_answer178)
  The electric potential inside a conducting sphere                                                                                              [RPMT 2002]
  A)
                     Increases from centre to surface done clear
  B)
                     Decreases from centre to surface done clear
  C)
                     Remains constant from centre to surface done clear
  D)
                     Is zero at every point inside done clear
  View Solution play_arrow

• question_answer179)
  The wrong statement about electric lines of force is                                                                                              [RPMT 2002]
  A)
                     These originate from positive charge and end on negative charge              done clear
  B)
                     They do not intersect each other at a point done clear
  C)
                     They have the same form for a point charge and a sphere done clear
  D)
                     They have physical existence done clear
  View Solution play_arrow

• question_answer180)
  A charge produces an electric field of 1 N/C at a point distant 0.1 m  from it. The magnitude of charge is                                                                                                [RPET 2002]
  A)
                     \[1.11\times {{10}^{-12}}\,C\] done clear
  B)
                                       \[9.11\times {{10}^{-12}}\,C\] done clear
  C)
                     \[7.11\times {{10}^{-6}}\,C\] done clear
  D)
                                       None of these done clear
  View Solution play_arrow

• question_answer181)
  A charged particle is suspended in equilibrium in a uniform vertical electric field of intensity 20000 V/m. If mass of the particle is \[9.6\times {{10}^{-16}}\,kg\], the charge on it and excess number of electrons on the particle are respectively \[(g=10\,m/{{s}^{2}})\]                                                                                   [Pb. PMT 2003]
  A)
                     \[4.8\times {{10}^{-19}}C,\,3\] done clear
  B)
                                       \[5.8\times {{10}^{-19}}C,\,4\] done clear
  C)
                     \[3.8\times {{10}^{-19}}C,\,2\] done clear
  D)
                     \[2.8\times {{10}^{-19}}C,\,1\] done clear
  View Solution play_arrow

• question_answer182)
  The potential at a distance R/2 from the centre of a conducting sphere of radius R will be              [RPMT 2003]
  A)
                     0                                         done clear
  B)
             \[\frac{Q}{8\pi {{\varepsilon }_{0}}R}\] done clear
  C)
                        \[\frac{Q}{4\pi {{\varepsilon }_{0}}R}\] done clear
  D)
             \[\frac{Q}{2\pi {{\varepsilon }_{0}}R}\] done clear
  View Solution play_arrow

• question_answer183)
  Four charges \[+Q,\,-Q,\,+Q,\,-Q\] are placed at the corners of a square taken in order. At the centre of the square                                                                                              [RPMT 2003]
  A)
                     \[E=0,\,V=0\] done clear
  B)
                                       \[E=0,\,V\ne 0\] done clear
  C)
                     \[E\ne 0,\,V=0\] done clear
  D)
                     \[E=0,\,V\ne 0\] done clear
  View Solution play_arrow

• question_answer184)
  The radius of nucleus of silver (atomic number = 47) is \[3.4\times {{10}^{-14}}m\]. The electric potential on the surface of nucleus is \[(e=1.6\times {{10}^{-19}}C)\]                                                       [Pb. PET 2003]
  A)
                     \[1.99\times {{10}^{6}}\,volt\] done clear
  B)
                                       \[2.9\times {{10}^{6}}\,volt\] done clear
  C)
                     \[4.99\times {{10}^{6}}\,volt\] done clear
  D)
                                       \[0.99\times {{10}^{6}}\,volt\] done clear
  View Solution play_arrow

• question_answer185)
  Charges q, 2q, 3q and 4q are placed at the corners A, B, C and D of a square as shown in the following figure. The direction of electric field at the centre of the square is along [MP PMT 2004
  A)
             AB done clear
  B)
                                       CB done clear
  C)
             BD done clear
  D)
             AC done clear
  View Solution play_arrow

• question_answer186)
  Point charge \[{{q}_{1}}=2\mu C\] and \[{{q}_{2}}=-1\,\mu C\] are kept at points \[x=0\] and \[x=6\] respectively. Electrical potential will be zero at points                                                                [MP PMT 2004]
  A)
             \[x=2\] and \[x=9\] done clear
  B)
                                       \[x=1\] and \[x=5\] done clear
  C)
                     \[x=4\] and \[x=12\]  done clear
  D)
             \[x=-2\] and \[x=2\] done clear
  View Solution play_arrow

• question_answer187)
  Equipotential surfaces associated with an electric field which is increasing in magnitude along the x-direction are                                                                                              [AIIMS 2004]
  A)
                     Planes parallel to yz-plane done clear
  B)
                     Planes parallel to xy-plane done clear
  C)
                     Planes parallel to xz-plane done clear
  D)
                     Coaxial cylinders of increasing radii around the x-axis. done clear
  View Solution play_arrow

• question_answer188)
  A bullet of mass 2 gm is having a charge of \[2\,\mu C\]. Through what potential difference must it be accelerated, starting from rest, to acquire a speed of \[10\,m/s\] [CBSE PMT 2004]
  A)
                     5 kV done clear
  B)
                                       50 kV done clear
  C)
                     5 V done clear
  D)
                                       50 V done clear
  View Solution play_arrow

• question_answer189)
  The           points resembling equal potentials are                                                                                      [Orissa PMT 2004]
  A)
                     P and Q done clear
  B)
                     S and Q done clear
  C)
                     S and R done clear
  D)
                     P and R done clear
  View Solution play_arrow

• question_answer190)
  Figure shows three points A, B and C in a region of uniform electric field \[\overrightarrow{E}\]. The line AB is perpendicular and BC is parallel to the field lines. Then which of the following holds good. Where \[{{V}_{A}},{{V}_{B}}\] and \[{{V}_{C}}\] represent the electric potential at points A, B and C respectively [CPMT 2004; MP PMT 2005]
  A)
             \[{{V}_{A}}={{V}_{B}}={{V}_{C}}\] done clear
  B)
             \[{{V}_{A}}={{V}_{B}}>{{V}_{C}}\] done clear
  C)
                     \[{{V}_{A}}={{V}_{B}}<{{V}_{C}}\] done clear
  D)
                     \[{{V}_{A}}>{{V}_{B}}={{V}_{C}}\] done clear
  View Solution play_arrow

• question_answer191)
  In a certain charge distribution, all points having zero potential can be joined by a circle S. Points inside S have positive potential and points outside S have negative potential. A positive charge, which is free to move, is placed inside S                                                                      [DPMT 2004]
  A)
                     It will remain in equilibrium done clear
  B)
                     It can move inside S, but it cannot cross S done clear
  C)
                     It must cross S at some time done clear
  D)
             It may move, but will ultimately return to its starting point done clear
  View Solution play_arrow

• question_answer192)
  Infinite charges of magnitude q each are lying at x =1, 2, 4, 8... meter on X-axis. The value of intensity of electric field at point x = 0 due to these charges will be   [J & K CET 2004]
  A)
             \[12\times {{10}^{9}}q\text{ }N/C\]                               done clear
  B)
             Zero done clear
  C)
             6 ´ 109q N/C done clear
  D)
                                       4 ´ 109q N/C done clear
  View Solution play_arrow

• question_answer193)
  A square of side ?a? has charge Q at its centre and charge ?q? at one of the corners. The work required to be done in moving the charge ?q? from the corner to the diagonally opposite corner is                                           [UPSEAT 2004]
  A)
             Zero done clear
  B)
             \[\frac{Qq}{4\pi {{\in }_{0}}a}\] done clear
  C)
                     \[\frac{Qq\sqrt{2}}{4\pi {{\in }_{0}}a}\] done clear
  D)
                                       \[\frac{Qq}{2\pi {{\in }_{0}}a}\] done clear
  View Solution play_arrow

• question_answer194)
  A pendulum bob of mass \[30.7\times {{10}^{-6}}\,kg\] and carrying a charge \[2\times {{10}^{-8}}\,C\] is at rest in a horizontal uniform electric field of 20000 V/m. The tension in the thread of the pendulum is \[(g=9.8\,m/{{s}^{2}})\]                                                                      [UPSEAT 2004]
  A)
                     \[3\times {{10}^{-4}}\,N\] done clear
  B)
                                       \[4\times {{10}^{-4}}\,N\] done clear
  C)
                     \[5\times {{10}^{-4}}\,N\] done clear
  D)
                                       \[6\times {{10}^{-4}}\,N\] done clear
  View Solution play_arrow

• question_answer195)
  An infinite line charge produce a field of \[7.182\times {{10}^{8}}\,N/C\] at a distance of 2 cm. The linear charge density is [MH CET 2004]
  A)
                     \[7.27\times {{10}^{-4}}\,C/m\] done clear
  B)
                                       \[7.98\times {{10}^{-4}}\,C/m\] done clear
  C)
                     \[7.11\times {{10}^{-4}}\,C/m\] done clear
  D)
                                       \[7.04\times {{10}^{-4}}\,C/m\] done clear
  View Solution play_arrow

• question_answer196)
  An electron experiences a force equal to its weight when placed in an electric field. The intensity of the field will be                                                                                            [MHCET 2004]
  A)
                     \[1.7\times {{10}^{-11}}\,N/C\] done clear
  B)
                                       \[5.0\times {{10}^{-11}}\,N/C\] done clear
  C)
                     \[5.5\times {{10}^{-11}}\,N/C\] done clear
  D)
             56 N/C done clear
  View Solution play_arrow

• question_answer197)
  The dielectric strength of air at NTP is \[3\times {{10}^{6}}\,V/m\] then the maximum charge that can be given to a spherical conductor of radius 3 m is                                                                         [Pb. PMT 2001]
  A)
             \[3\times {{10}^{-4}}C\] done clear
  B)
                                       \[3\times {{10}^{-3}}C\] done clear
  C)
             \[3\times {{10}^{-2}}C\] done clear
  D)
                                       \[3\times {{10}^{-1}}C\] done clear
  View Solution play_arrow

• question_answer198)
  As per this diagram a point charge \[+q\] is placed at the origin \[O\]. Work done in taking another point charge \[-Q\] from the point \[A\] [co-ordinates \[(0,\,a)\]] to another point B [co-ordinates (a, 0)] along the straight path \[AB\] is [CBSE PMT 2005]
  A)
             Zero done clear
  B)
             \[\left( \frac{-qQ}{4\pi {{\varepsilon }_{0}}}\frac{1}{{{a}^{2}}} \right)\,\sqrt{2}a\] done clear
  C)
             \[\left( \frac{qQ}{4\pi {{\varepsilon }_{0}}}\frac{1}{{{a}^{2}}} \right)\,\frac{a}{\sqrt{2}}\] done clear
  D)
             \[\left( \frac{qQ}{4\pi {{\varepsilon }_{0}}}\frac{1}{{{a}^{2}}} \right)\,\sqrt{2}a\] done clear
  View Solution play_arrow

• question_answer199)
  To charges \[{{q}_{1}}\] and \[{{q}_{2}}\] are placed \[30\,\,cm\] apart, shown in the figure. A third charge \[{{q}_{3}}\]is moved along the arc of a circle of radius \[40\,cm\] from \[C\] to D. The change in the potential energy of the system is \[\frac{{{q}_{3}}}{4\pi {{\varepsilon }_{0}}}k\], where \[k\] is [CBSE PMT 2005]
  A)
             \[8\,{{q}_{2}}\] done clear
  B)
             \[8\,{{q}_{1}}\] done clear
  C)
             \[6{{q}_{2}}\] done clear
  D)
             \[6{{q}_{1}}\] done clear
  View Solution play_arrow

• question_answer200)
  A charged ball B hangs from a silk thread S, which makes an angle \[\theta \] with a large charged conducting sheet \[P\], as shown in the figure. The surface charge density \[\sigma \] of the sheet is proportional to                                             [AIEEE 2005]
  A)
             \[\sin \theta \] done clear
  B)
             \[\tan \theta \] done clear
  C)
             \[\cos \theta \] done clear
  D)
             \[\cot \theta \] done clear
  View Solution play_arrow

• question_answer201)
  Two point charges +8q  and \[-2q\] are located at \[x=0\] and \[x=L\] respectively. The location of a point on the x-axis at which the net electric field due to these two point charges is zero is                                          [AIEEE 2005]
  A)
             8 L done clear
  B)
             4 L done clear
  C)
             2 L done clear
  D)
             \[\frac{L}{4}\] done clear
  View Solution play_arrow

• question_answer202)
  Two thin wire rings each having a radius R are placed at  a distance d apart with their axes coinciding. The charges on the two rings are \[+q\] and \[-q\]. The potential difference between the centres of the two rings is      [AIEEE 2005]
  A)
             Zero                                          done clear
  B)
             \[\frac{Q}{4\pi {{\varepsilon }_{0}}}\,\left[ \frac{1}{R}-\frac{1}{\sqrt{{{R}^{2}}+{{d}^{2}}}} \right]\] done clear
  C)
                                       \[QR/4\pi {{\varepsilon }_{0}}{{d}^{2}}\] done clear
  D)
                                       \[\frac{Q}{2\pi {{\varepsilon }_{0}}}\left[ \frac{1}{R}-\frac{1}{\sqrt{{{R}^{2}}+{{d}^{2}}}} \right]\] done clear
  View Solution play_arrow

• question_answer203)
  Three infinitely long charge sheets are placed as shown in figure. The electric field at point P is [IIT-JEE (Screening) 2005]
  A)
                                             \[\frac{2\sigma }{{{\varepsilon }_{o}}}\]\[\hat{k}\]                         done clear
  B)
              \[-\frac{2\sigma }{{{\varepsilon }_{o}}}\]\[\hat{k}\] done clear
  C)
              \[\frac{4\sigma }{{{\varepsilon }_{o}}}\]\[\hat{k}\] done clear
  D)
                                        \[-\frac{4\sigma }{{{\varepsilon }_{o}}}\]\[\hat{k}\] done clear
  View Solution play_arrow

• question_answer204)
  Two infinitely long parallel conducting plates having surface charge densities \[+\sigma \]and\[-\sigma \]respectively, are separated by a small distance. The medium between the plates is vacuum. If \[{{\varepsilon }_{0}}\]is the dielectric permittivity of vacuum, then the electric field in the region between the plates is               [AIIMS 2005]
  A)
             \[0\,volts/meter\] done clear
  B)
                                       \[\frac{\sigma }{2{{\varepsilon }_{o}}}volts/meter\] done clear
  C)
             \[\frac{\sigma }{{{\varepsilon }_{o}}}volts/meter\] done clear
  D)
                                       \[\frac{2\sigma }{{{\varepsilon }_{o}}}volts/meter\] done clear
  View Solution play_arrow

• question_answer205)
  Four point +ve charges of same magnitude (Q) are placed at four corners of a rigid square frame as shown in figure. The plane of the frame is perpendicular to \[\]axis. If a ?ve point charge is placed at a distance z away from the above frame (z<<L) then                                                        [AIIMS 2005]
  A)
             ? ve charge oscillates along the \[\]axis. done clear
  B)
             It moves away from the frame done clear
  C)
             It moves slowly towards the frame and stays in the plane of the frame       done clear
  D)
             It passes through the frame only once. done clear
  View Solution play_arrow

• question_answer206)
  At a point 20 cm from the centre of a uniformly charged dielectric sphere of radius 10 cm, the electric field is 100 V/m. The electric field at 3 cm from the centre of the sphere will be                                   [BCECE 2005]
  A)
             150 V/m done clear
  B)
                                       125 V/m done clear
  C)
             120 V/m done clear
  D)
                                       Zero done clear
  View Solution play_arrow

• question_answer207)
  Charges 4Q, q and Q and placed along x-axis at positions \[x=0,x=l/2\] and \[x=l\], respectively. Find the value of q so that force on charge Q is zero           [DPMT 2005]
  A)
             Q    done clear
  B)
             Q / 2 done clear
  C)
             ? Q / 2 done clear
  D)
                                       ? Q done clear
  View Solution play_arrow

• question_answer208)
  If an electron moves from rest from a point at which potential is 50 volt to another point at which potential is 70 volt, then its kinetic energy in the final state will be [J & K CET 2005]
  A)
             3.2 × 10?10 J done clear
  B)
                                       3.2 × 10?18 J done clear
  C)
             1 N done clear
  D)
             1 dyne done clear
  View Solution play_arrow

• question_answer209)
  In the following diagram the work done in moving a point charge from point P to point A, B and C is respectively as \[{{W}_{A}}\],\[~{{W}_{B}}\] and \[{{W}_{C}}\], then                                     [J & K CET 2005]
  A)
             \[{{W}_{A}}=\text{ }{{W}_{B}}=\text{ }{{W}_{C}}\] done clear
  B)
             \[{{W}_{A}}=\text{ }{{W}_{B}}=\text{ }{{W}_{C}}=\text{ }0\] done clear
  C)
             \[{{W}_{A}}>\text{ }{{W}_{B}}>\text{ }{{W}_{C}}\] done clear
  D)
             \[{{W}_{A}}<\text{ }{{W}_{B}}<\text{ }{{W}_{C}}\] done clear
  View Solution play_arrow

• question_answer210)
  A hollow metallic sphere of radius R is given a charge Q. Then the potential at the centre is          [Orissa JEE 2005]
  A)
             Zero                                          done clear
  B)
             \[\frac{1}{4\pi {{\varepsilon }_{0}}}.\frac{Q}{R}\] done clear
  C)
                     \[\frac{1}{4\pi {{\varepsilon }_{0}}}.\frac{2Q}{R}\] done clear
  D)
                                               \[\frac{1}{4\pi {{\varepsilon }_{0}}}.\frac{Q}{2R}\] done clear
  View Solution play_arrow