JEE Main & Advanced Physics Current Electricity, Charging & Discharging Of Capacitors / वर्तमान बिजली, चार्ज और कैपेसिटर का निर Question Bank

done Self Evaluation Test - Current Electricity Total Questions - 100

• question_answer1)
  The total momentum of electrons in a straight wire of length 1000m carrying a current of 70A is closest to
  A)
  \[40\times {{10}^{-8}}N-\sec \] done clear
  B)
  \[30\times {{10}^{-8}}N-\sec \] done clear
  C)
  \[50\times {{10}^{-8}}N-\sec \] done clear
  D)
  \[70\times {{10}^{-8}}N-\sec \] done clear
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• question_answer2)
  The resistance of a wire is R. It is bent at the middle by \[180{}^\circ \] and both the ends are twisted together to make a shorter wire. The resistance of the new wire is
  A)
  2R        done clear
  B)
  R/2       done clear
  C)
  R/4 done clear
  D)
  R/8 done clear
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• question_answer3)
  Suppose the drift velocity \[{{v}_{d}}\]in a material varied with the applied electric field E as \[{{v}_{d}}\propto \sqrt{E}.\] Then V-I graph for a wire made of such a material is best given by:
  A)
  done clear
  B)
  done clear
  C)
  done clear
  D)
  done clear
  View Solution play_arrow

• question_answer4)
  The current density varies with radial distance r as\[j=a{{r}^{2}}\], in a cylindrical wire of radius R. The current passing through the wire between radial distance R/3 and R/2 is
  A)
  \[\frac{65\pi a{{R}^{4}}}{2592}\] done clear
  B)
  \[\frac{25\pi a{{R}^{4}}}{72}\] done clear
  C)
  \[\frac{65\pi {{a}^{2}}{{R}^{3}}}{2938}\] done clear
  D)
  \[\frac{81\pi {{a}^{2}}{{R}^{4}}}{144}\] done clear
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• question_answer5)
  In a certain paricle accelerator, electrons emerge in pulses at the rate of 250 pulses per second. Each pulse is of duration of 200ns and the electrons in the pulse constitute a current of 250mA. The number of electrons delivered by the accelerator per pulse is
  A)
  \[8.00\times {{10}^{10}}\] done clear
  B)
  \[5.00\times {{10}^{10}}\] done clear
  C)
  \[3.13\times {{10}^{11}}\] done clear
  D)
  \[9.60\times {{10}^{10}}\] done clear
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• question_answer6)
  Two wires of the same metal have same length, but their cross-sections are in the ratio 3 : 1. They are joined in series. The resistance of thicker wire is \[10\Omega .\]The total resistance of the combination will be
  A)
  \[10\Omega \] done clear
  B)
  \[20\Omega \] done clear
  C)
  \[40\Omega \] done clear
  D)
  \[100\Omega \] done clear
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• question_answer7)
  In the network shown, each resistance is equals to R. The equivalent resistance between adjacent corners A and D is
  A)
  \[R\] done clear
  B)
  \[\frac{2}{3}R\] done clear
  C)
  \[\frac{3}{7}R\] done clear
  D)
  \[\frac{8}{15}R\] done clear
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• question_answer8)
  Drift velocity of electrons is due to
  A)
  motion of conduction electrons due to random collisions. done clear
  B)
  motion of conduction electrons due to electric field \[\vec{E}.\] done clear
  C)
  repulsion to the conduction electrons due to inner electrons of ions. done clear
  D)
  collision of conduction electrons with each other. done clear
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• question_answer9)
  A metal wire is subjected to a constant potential difference. When the temperature of the metal wire increases, the drift velocity of the electron in it
  A)
  increases, thermal velocity of the electron increases done clear
  B)
  decreases, thermal velocity of the electron increases done clear
  C)
  increases, thermal velocity of the electron decreases done clear
  D)
  decreases, thermal velocity of the electron decreases done clear
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• question_answer10)
  If N, e, \[\tau \]and m are representing electron density, charge, relaxation time and mass of an electron respectively, then the resistance of wire of length l and cross-sectional area A is given by
  A)
  \[\frac{ml}{N{{e}^{2}}{{A}^{2}}\tau }\] done clear
  B)
  \[\frac{2m\tau A}{N{{e}^{2}}l}\] done clear
  C)
  \[\frac{N{{e}^{2}}\tau A}{2ml}\] done clear
  D)
  \[\frac{N{{e}^{2}}}{2m\tau l}\] done clear
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• question_answer11)
  The electric resistance of a certain wire of iron is R. If its length and radius are both doubled, then
  A)
  the resistance and the specific resistance, will both remain unchanged   done clear
  B)
  the resistance will be doubled and the specific resistance will be halved done clear
  C)
  the resistance will be halved and the specific resistance will be remain unchanged   done clear
  D)
  the resistance will be halved and the specific resistance will be doubled done clear
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• question_answer12)
  A wire X is half the diameter and half the length of a wire Y of similar material. The ratio of resistance of X to that of Y is
  A)
  8 : 1      done clear
  B)
  4 : 1 done clear
  C)
  2 : 1      done clear
  D)
  1 : 1 done clear
  View Solution play_arrow

• question_answer13)
  The voltage V and current I graphs for a conductor at two different temperatures \[{{T}_{1}}\]and \[{{T}_{2}}\]are shown in the figure. The relation between \[{{T}_{1}}\]and \[{{T}_{2}}\]is
  A)
  \[{{T}_{1}}>{{T}_{2}}\] done clear
  B)
  \[{{T}_{1}}<{{T}_{2}}\] done clear
  C)
  \[{{T}_{1}}={{T}_{2}}\] done clear
  D)
  \[{{T}_{1}}=\frac{1}{{{T}_{2}}}\] done clear
  View Solution play_arrow

• question_answer14)
  The amount of charge Q passed in time t through a cross-section of a wire is \[Q=5{{t}^{2}}+3t+1.\] The value of current at time t=5 s is
  A)
  9 A    done clear
  B)
  49 A done clear
  C)
  53 A done clear
  D)
  None of these done clear
  View Solution play_arrow

• question_answer15)
  A conductor carries a current of \[50\mu A.\] If the area of cross-section of the conductor is \[50m{{m}^{2}}\], then value of the current density in \[A{{m}^{-2}}\]is
  A)
  0.5 done clear
  B)
  1 done clear
  C)
  \[{{10}^{-3}}\]            done clear
  D)
  \[{{10}^{-6}}\] done clear
  View Solution play_arrow

• question_answer16)
  The resistance of a wire is R. It is bent at the middle by \[180{}^\circ \] and both the ends are twisted together to make a shorter wire. The resistance of the new wire is copper wire becomes three times its value at \[0{}^\circ C\]?
  A)
  2R done clear
  B)
  R/2 done clear
  C)
  R/4 done clear
  D)
  R/8 done clear
  View Solution play_arrow

• question_answer17)
  At what temperature will the resistance of a copper wire becomes three times its value at \[0{}^\circ C\]? (Temperature coefficient of resistance of copper is \[4\times {{10}^{-3}}/{}^\circ C\] )
  A)
  \[550{}^\circ C\] done clear
  B)
  \[500{}^\circ C\] done clear
  C)
  \[450{}^\circ C\] done clear
  D)
  \[400{}^\circ C\] done clear
  View Solution play_arrow

• question_answer18)
  When a current I is set up in a wire of radius r, the drift velocity is \[{{v}_{d}}.\] If the same current is set up through a wire of radius 2 r, the drift velocity will be
  A)
  \[4{{v}_{d}}\]   done clear
  B)
  \[2{{v}_{d}}\] done clear
  C)
  \[{{v}_{d}}/2\] done clear
  D)
  \[{{v}_{d}}/4\] done clear
  View Solution play_arrow

• question_answer19)
  A straight conductor of uniform cross-section carries a current I. Ifs is the specific charge of an electron, the momentum of all the free electrons per unit length of the conductor, due to their drift velocity only is
  A)
  \[I\,s~\] done clear
  B)
  \[\sqrt{I/s}\] done clear
  C)
  \[I/s~~~\] done clear
  D)
  \[{{\left( I/s \right)}^{2}}\] done clear
  View Solution play_arrow

• question_answer20)
  If the resistance of a conductor is \[5\Omega \] at \[50{}^\circ C\]& \[7\Omega \] at \[100{}^\circ C,\] then mean temperature coefficient
  A)
  \[0.013/{}^\circ C~\] done clear
  B)
  \[0.004/{}^\circ C\] done clear
  C)
  \[0.006/{}^\circ C\] done clear
  D)
  \[0.008/{}^\circ C\] done clear
  View Solution play_arrow

• question_answer21)
  If negligibly small current is passed through a wire of length 15 m and resistance of \[5\Omega \], having uniform cross section of \[6\times {{10}^{-7}}{{m}^{2}}\], then coefficient of resistivity of material is
  A)
  \[1\times {{10}^{-7}}\Omega -m\] done clear
  B)
  \[2\times {{10}^{-7}}\Omega -m\] done clear
  C)
  \[3\times {{10}^{-7}}\Omega -m\] done clear
  D)
  \[4\times {{10}^{-7}}\Omega -m\] done clear
  View Solution play_arrow

• question_answer22)
  The resistance of a wire at room temperature \[30{}^\circ C\]is found to be \[10\Omega .\] Now to be increase the resistance by 10%, the temperature of the wire must be [The temperature coefficient of resistance of the material of the wire is 0.002 per \[{}^\circ C\]]
  A)
  \[36{}^\circ C\] done clear
  B)
  \[83{}^\circ C\] done clear
  C)
  \[63{}^\circ C\] done clear
  D)
  \[33{}^\circ C\] done clear
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• question_answer23)
  The number of free electrons per 100 mm of ordinary copper wire is \[2\times {{10}^{21}}.\] Average drift speed of electrons is 0.25 mm/s. The current flowing is
  A)
  5 A       done clear
  B)
  80 A done clear
  C)
  8 A done clear
  D)
  0.8 A done clear
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• question_answer24)
  At room temperature, copper has free electron density of \[8.4\times {{10}^{28}}\] per \[{{m}^{3}}.\] The copper conductor has a cross-section of \[{{10}^{-6}}m\] and velocity in copper is   
  A)
  \[36{}^\circ C\] done clear
  B)
  \[83{}^\circ C\] done clear
  C)
  \[63{}^\circ C\] done clear
  D)
  \[33{}^\circ C\] done clear
  View Solution play_arrow

• question_answer25)
  An electron beam has an aperture \[1.0m{{m}^{2}}.\] A total of \[6\times {{10}^{6}}\] electrons go through any perpendicular cross section per second. Find the current density in the beam. (in \[A/{{m}^{2}}\])
  A)
  \[9.1\times {{10}^{13}}\] done clear
  B)
  \[9.6\times {{10}^{3}}\] done clear
  C)
  \[6.6\times {{10}^{5}}\] done clear
  D)
  \[8.6\times {{10}^{11}}\] done clear
  View Solution play_arrow

• question_answer26)
  A wire of a certain material is stretched slowly by ten per cent. Its new resistance and specific resistance become respectively:
  A)
  1.2 times, 1.3 times done clear
  B)
  1.21 times, same done clear
  C)
  both remain the same done clear
  D)
  1.1 times, 1.1 times done clear
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• question_answer27)
  A 4 ohm resistance wire is bent through \[180{}^\circ C\] at its mid-point and the two halves are twisted together. Then the resistance is
  A)
  \[1\Omega \]      done clear
  B)
  \[2\Omega \] done clear
  C)
  \[5\Omega \] done clear
  D)
  \[8\Omega \] done clear
  View Solution play_arrow

• question_answer28)
  The length of a given cylindrical wire is increased by 100%. Due to the consequent decrease in diameter the change in the resistance of the wire will be
  A)
  200% done clear
  B)
  100% done clear
  C)
  50% done clear
  D)
  300% done clear
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• question_answer29)
  The masses of the three wires of copper are in the ratio of 1 : 3 : 5 and their lengths are in the ratio of 5 : 3 : 1. The ratio of their electrical resistance is
  A)
  1 : 3 : 5 done clear
  B)
  5 : 3 : 1 done clear
  C)
  1 : 25 : 125 done clear
  D)
  125 : 45 : 3 done clear
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• question_answer30)
  A uniform wire of length l and radius r has a resistance of \[100\Omega \]. It is recast into a wire of radius\[\frac{r}{2}\]. The resistance of new wire will be:
  A)
  \[1600\Omega \] done clear
  B)
  \[400\Omega \] done clear
  C)
  \[200\Omega \] done clear
  D)
  \[100\Omega \] done clear
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• question_answer31)
  A wire has a resistance \[12\Omega \]. It is bent in the form of a circle. The effective resistance between two points on any diameter is
  A)
              \[6\Omega \]      done clear
  B)
              \[3\Omega \]  done clear
  C)
  \[\,12\Omega \] done clear
  D)
  \[24\Omega \] done clear
  View Solution play_arrow

• question_answer32)
  In the network shown below, the ring has zero resistance. The equivalent resistance between the point A and B is
  A)
  2R done clear
  B)
  4R done clear
  C)
  7R done clear
  D)
  10R done clear
  View Solution play_arrow

• question_answer33)
  The equivalent resistance between points A and B is
  A)
  2R done clear
  B)
  (3/4)R done clear
  C)
  (4/3)R done clear
  D)
  (3/5)R done clear
  View Solution play_arrow

• question_answer34)
  Six equal resistances are connected between points P, Q and R as shown in figure. Then net resistance will be maximum between:
  A)
  P and R done clear
  B)
  P and Q done clear
  C)
  Q and R done clear
  D)
  any two points done clear
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• question_answer35)
  The current in the \[1\Omega \] resistor shown in the circuit is
  A)
  \[\frac{2}{3}A\] done clear
  B)
  \[3A\] done clear
  C)
  \[6A\] done clear
  D)
  \[2A\] done clear
  View Solution play_arrow

• question_answer36)
  A wire of resistance 12 ohms per meter is bent to from a complete circle of radius 10 cm. The resistance between its two diametrically opposite points, A and B as shown in the figure, is
  A)
  \[3\Omega \]                  done clear
  B)
         \[6\pi \Omega \] done clear
  C)
  \[6\Omega \]                  done clear
  D)
         \[0.6\pi \Omega \] done clear
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• question_answer37)
  A wire has linear resistance \[\rho \](in Ohm/m). Find the resistance R between points A and B if the side of the larger square is 'd'.       
  A)
  \[\rho d/\sqrt{2}\]            done clear
  B)
  \[\sqrt{2}\rho d\] done clear
  C)
  \[2rd\]                done clear
  D)
  None of these done clear
  View Solution play_arrow

• question_answer38)
  Six identical resistors are connected as shown in the figure. The equivalent resistance will be     
  A)
  maximum between P and R done clear
  B)
  maximum between Q and R done clear
  C)
  maximum between P and Q done clear
  D)
  All are equal   done clear
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• question_answer39)
  The circuit diagram shown in figure consists of a very large (infinite) number of elements. The resistances of the resistors in each subsequent element differ by a factor of k from the resistances of the resistors in the previous elements. Determine the resistance \[{{R}_{AB}}\] between points A and B if the resistances of the first element are \[{{R}_{1}}\] and\[{{R}_{2}}\]. (k=1/2)
  A)
  \[\frac{{{R}_{1}}-{{R}_{2}}+\sqrt{R_{1}^{2}+R_{2}^{2}+6{{R}_{1}}{{R}_{2}}}}{2}\] done clear
  B)
  \[\frac{{{R}_{1}}+{{R}_{2}}+\sqrt{R_{1}^{2}+R_{2}^{2}+6{{R}_{1}}{{R}_{2}}}}{2}\] done clear
  C)
  \[\frac{{{R}_{1}}-{{R}_{2}}-\sqrt{R_{1}^{2}+R_{2}^{2}+6{{R}_{1}}{{R}_{2}}}}{2}\]                               done clear
  D)
  None of these done clear
  View Solution play_arrow

• question_answer40)
  Each of the resistors shown in Fig. has resistance R. Find the equivalent resistance between A and B.
  A)
  \[\frac{7R}{4}\] done clear
  B)
  \[\frac{5R}{4}\] done clear
  C)
  \[\frac{9R}{4}\] done clear
  D)
  \[\frac{11R}{4}\] done clear
  View Solution play_arrow

• question_answer41)
  Find the equivalent resistance between A and B (resistance of each resistor is R.)
  A)
  \[\frac{7}{12}R\] done clear
  B)
  \[\frac{7}{13}R\] done clear
  C)
  \[\frac{7}{15}R\] done clear
  D)
  \[\frac{8}{13}R\] done clear
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• question_answer42)
  In Fig. find the value of resistor to be connected between C and D, so that the resistance of the entire circuit between A and B does not change with the number of elementary seta.
  A)
  \[R\] done clear
  B)
  \[R\left( \sqrt{3}-1 \right)\] done clear
  C)
  \[3R\] done clear
  D)
  \[R\left( \sqrt{3}+1 \right)\] done clear
  View Solution play_arrow

• question_answer43)
  A hank of uninsulated wire consisting of seven and a half turns is stretched between two nails hammered into a board to which the ends of the wire are fixed. The resistance of the circuit between the nails is determined with the help of electrical measuring instruments. Determine the proportion in which the resistance will change if the wire is unwound so that the ends remain to be fixed to the nails.
  A)
  225 done clear
  B)
  15 done clear
  C)
  240 done clear
  D)
  250 done clear
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• question_answer44)
  A 12 cm wire is given a shape of a right angled triangle ABC having sides 3 cm, 4 cm and 5 cm as shown in the figure. The resistance between two ends (AB, BC, CA) of the respective sides are measured one by one a multi-meter. The resistances will be in the ratio of  
  A)
  3 : 4 : 5 done clear
  B)
  9 : 16 : 25 done clear
  C)
  27 : 32 : 35 done clear
  D)
  21 : 24 : 25 done clear
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• question_answer45)
  What will be the change in the resistance of a circuit consisting of five identical conductors if two similar conductors are added as shown by the dashed line in figure.
  A)
  becomes 1/5 times          done clear
  B)
  becomes 3/5 times done clear
  C)
  becomes 2/5 times done clear
  D)
  becomes 1/2 times done clear
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• question_answer46)
  A wire of resistance 12 ohms per meter is bent to form a square of total length 10 cm. The resistance between its two forthest points is
  A)
  \[1.2\Omega \] done clear
  B)
  \[6\Omega \] done clear
  C)
  \[1.5\Omega \] done clear
  D)
  \[2.8\Omega \] done clear
  View Solution play_arrow

• question_answer47)
  The Kirchhoff?s second law \[\left( \Sigma R\text{ }=\text{ }\Sigma E \right),\]where the symbols have their usual meanings, is based on
  A)
  conservation of momemtum done clear
  B)
  conservation of charge done clear
  C)
  conservation of potential              done clear
  D)
  conservation of energy done clear
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• question_answer48)
  A cell of internal resistance r is connected to an external resistance R. The current will be maximum in R, if
  A)
  \[R=r\] done clear
  B)
  \[R<r\] done clear
  C)
  \[R>r\] done clear
  D)
  \[\,R=r/2\] done clear
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• question_answer49)
  If n cells each of emf \[\varepsilon \]and internal resistance r are connected in parallel, then the total emf and internal resistances will be
  A)
  \[\varepsilon ,\frac{r}{n}\]           done clear
  B)
  \[\varepsilon ,nr\] done clear
  C)
  \[n\varepsilon ,\frac{r}{n}\] done clear
  D)
  \[n\varepsilon ,rn\] done clear
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• question_answer50)
    Under what condition will the strength of current in a wire of resistance R be the same for connection is series and in parallel of n identical cells each of the internal resistance?
  A)
  \[R=nr\] done clear
  B)
  \[R=r/n\] done clear
  C)
  \[R=r\] done clear
  D)
  \[R\to \infty ,r\to 0\] done clear
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• question_answer51)
  A cell having an emf \[\varepsilon \]and internal resistance r is connected across a variable external resistance R. As the resistance R is increased, the plot of potential difference V across R is given by
  A)
  done clear
  B)
    done clear
  C)
  done clear
  D)
  done clear
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• question_answer52)
  The internal resistance of a 2.1 V cell which gives a current of 0.2 A through a resistance of \[10\Omega \]is
  A)
  \[0.5\Omega \] done clear
  B)
  \[0.8\Omega \] done clear
  C)
  \[1.0\Omega \] done clear
  D)
  \[0.2\Omega \] done clear
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• question_answer53)
  A primary cell has an e.m.f. of 1.5 volt. When short-circuited it gives a current of 3 ampere. The internal resistance of the cell is
  A)
  4.5 ohm done clear
  B)
  2 ohm done clear
  C)
  0.5 ohm done clear
  D)
  (1/4.5) ohm done clear
  View Solution play_arrow

• question_answer54)
  In the given network of four resistances, the equivalent resistance is:
  A)
  \[20\Omega \] done clear
  B)
  \[5.4\Omega \] done clear
  C)
  \[12\Omega \]     done clear
  D)
  \[4.5\Omega \]      done clear
  View Solution play_arrow

• question_answer55)
  In the given mesh, each resistor has resistance R. The effective resistance between the terminals A and B is  
  A)
  \[\frac{3R}{8}\] done clear
  B)
  \[\frac{R}{2}\] done clear
  C)
  \[R\] done clear
  D)
  \[2R\] done clear
  View Solution play_arrow

• question_answer56)
  All wires have same resistance and equivalent resistance between A and B is Ry. Now keys are closed, then the equivalent resistance will become
  A)
  \[\frac{7{{R}_{0}}}{3}\] done clear
  B)
  \[\frac{7{{R}_{0}}}{9}\] done clear
  C)
  \[7{{R}_{0}}\] done clear
  D)
  \[\frac{{{R}_{0}}}{3}\] done clear
  View Solution play_arrow

• question_answer57)
  Find equivalent resistance between A&B in the following circuit
  A)
  \[\frac{3R}{2}\] done clear
  B)
  \[\frac{2R}{3}\] done clear
  C)
  \[2R\] done clear
  D)
  \[3R\] done clear
  View Solution play_arrow

• question_answer58)
  The effective resistance between the terminals
  A)
  \[5\Omega \] done clear
  B)
  \[10\Omega \] done clear
  C)
  \[15\Omega \]     done clear
  D)
  \[20\Omega \] done clear
  View Solution play_arrow

• question_answer59)
  Determine the current in \[2\Omega \]resistor.
  A)
  1 A       done clear
  B)
  1.5 A done clear
  C)
  0.9 A done clear
  D)
  0.6 A done clear
  View Solution play_arrow

• question_answer60)
  Two sources of equal emf are connected to an external resistance R. The identical resistance of the two sources are \[{{R}_{1}}\] and \[{{R}_{2}}\]\[\left( {{R}_{2}}>{{R}_{1}} \right)\]. If the potential difference across the source having internal resistance \[{{R}_{2}}\]is zero, then
  A)
  \[R={{R}_{2}}-{{R}_{1}}\] done clear
  B)
  \[R={{R}_{2}}\times \left( {{R}_{1}}+{{R}_{2}} \right)/\left( {{R}_{2}}-{{R}_{1}} \right)\] done clear
  C)
  \[R={{R}_{1}}{{R}_{2}}/\left( {{R}_{2}}-{{R}_{1}} \right)\] done clear
  D)
  \[R={{R}_{1}}{{R}_{2}}/\left( {{R}_{1}}-{{R}_{2}} \right)\] done clear
  View Solution play_arrow

• question_answer61)
  In the series combination of« cells each cell having emfs and internal resistance r. It three cells are wrongly connected, then total emf and internal resistance of this combination will be
  A)
  \[n\varepsilon ,\left( nr-3r \right)\] done clear
  B)
  \[\left( n\varepsilon -2\varepsilon  \right)nr\] done clear
  C)
  \[\left( n\varepsilon -4\varepsilon  \right)nr\] done clear
  D)
  \[\left( n\varepsilon -6\varepsilon  \right)nr\] done clear
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• question_answer62)
  A 3 volt battery with negligible internal resistance is connected in a circuit as shown in the figure.
  A)
  1 A done clear
  B)
  1.5 A done clear
  C)
  2 A done clear
  D)
  1/3 A done clear
  View Solution play_arrow

• question_answer63)
  The four wires from a larger circuit intersect at junction A as shown. What is the magnitude and direction of the current between points A and B?
  A)
  2A from A to B done clear
  B)
  2A from B to A done clear
  C)
  3A from A to B done clear
  D)
  2A from B to A done clear
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• question_answer64)
  A battery of emf 10V and internal resistance 30hm is connected to a resister. The current in the circuit is 0.5 amp. The terminal voltage of the battery when the circuit is closed is
  A)
  10V      done clear
  B)
  zero done clear
  C)
  1.5V     done clear
  D)
  8.5V done clear
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• question_answer65)
  Five cells each of emf E and internal resistance r send the same amount of current through an external resistance R whether the cells are connected in parallel or in series. Then the ratio \[\left( \frac{R}{r} \right)\] is
  A)
  \[2\] done clear
  B)
  \[\frac{1}{2}\] done clear
  C)
  \[\frac{1}{5}\] done clear
  D)
  \[1\] done clear
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• question_answer66)
  Three batteries of emf 1V and internal resistance \[1\Omega \]each are connected as shown. Effective emf of combination between the points PQ is 
  A)
  zero       done clear
  B)
  1V done clear
  C)
  2V done clear
  D)
  (2/3)V done clear
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• question_answer67)
  In the circuit shown in Figure the current through
  A)
  the \[3\Omega \]resistor is 0.50 A. done clear
  B)
  the \[3\Omega \]resistor is 0.25 A. done clear
  C)
  the \[4\Omega \]resistor is 0.50 A. done clear
  D)
  the \[4\Omega \]resistor is 0.25 A. done clear
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• question_answer68)
  In the circuit shown in the figure, find the current in \[45\Omega \].
  A)
  4 A done clear
  B)
  2.5 A done clear
  C)
  2 A done clear
  D)
  None of these done clear
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• question_answer69)
  A, B and C are voltmeters of resistance R, 1.5R and 3R respectively as shown in the figure. When some potential difference is applied between X and Y, the voltmeter readings are \[{{V}_{A}},{{V}_{B}}\]and \[{{V}_{C}}\]respectively. Then
  A)
  \[{{V}_{A}}\ne {{V}_{B}}={{V}_{C}}\] done clear
  B)
  \[{{V}_{A}}={{V}_{B}}\ne {{V}_{C}}\] done clear
  C)
  \[{{V}_{A}}\ne {{V}_{B}}\ne {{V}_{C}}\]       done clear
  D)
  \[{{V}_{A}}={{V}_{B}}={{V}_{C}}\] done clear
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• question_answer70)
  A 9 V battery with internal resistance of 0.512 is connected across an infinite network as shown in the figure. All ammeters \[{{A}_{1}},{{A}_{2}},{{A}_{3}}\]and voltmeter V are ideal. Choose correct statement.  
  A)
  Reading of \[A{{  }_{1}}\] is 2 A   done clear
  B)
  Reading of \[A{{  }_{1}}\]is 18 A done clear
  C)
  Reading of V is 9 V done clear
  D)
  Reading of V is 7 V done clear
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• question_answer71)
  Two batteries of emf 4 V and 8 V with internal resistance \[1\Omega \] and \[2\Omega \]are connected in a circuit with a resistance of \[9\Omega \] as shown in figure. The current and potential difference between the points P and Q are
  A)
  \[\frac{1}{3}A\]and 3 V done clear
  B)
  \[\frac{1}{6}A\] and 4 V done clear
  C)
  \[\frac{1}{9}A\] and 9 V done clear
  D)
  \[\frac{1}{12}A\] and 12 V done clear
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• question_answer72)
  Find out the value of current through \[2\Omega \]resistance for the given circuit.
  A)
  zero done clear
  B)
  2A done clear
  C)
  5A done clear
  D)
  4A done clear
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• question_answer73)
  The circuit shown here has two batteries of 8.0 V and 16.0 V and three resistors \[3\Omega \], \[9\Omega \,\] and \[9\Omega \,\] a capacitor of \[5.0\text{ }\mu F.\] How much is the current I in the circuit in steady state?          
  A)
  1.6 A done clear
  B)
  0.67 A done clear
  C)
  2.5 A done clear
  D)
  0.25 A done clear
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• question_answer74)
  In the circuit shown, current (in A) through 50 V and 30 V batteries are, respectively.
  A)
  2.5 and 3 done clear
  B)
  3.5 and 2 done clear
  C)
  4.5 and 1 done clear
  D)
  3 and 2.5 done clear
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• question_answer75)
  Cell having an emf \[\varepsilon \] and internal resistance r is As the resistance R is increased, the plot of potential difference V across R is given by:
  A)
  done clear
  B)
  done clear
  C)
  done clear
  D)
  done clear
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• question_answer76)
  In the circuit shown in the figure, if potential at point A is taken to be zero, the potential at point B is
  A)
  -1V       done clear
  B)
  +2V done clear
  C)
  -2V done clear
  D)
  +1V done clear
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• question_answer77)
  Forty electric bulbs are connected in series across a 220 V supply. After one bulb is fused the remaining 39 are connected again in series across the same supply. The illumination will be
  A)
  more with 40 bulbs than with 39 done clear
  B)
  more with 39 bulbs than with 40 done clear
  C)
  equal in both the cases done clear
  D)
  in the ratio \[{{40}^{2}}:{{39}^{2}}\] done clear
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• question_answer78)
  A current of 3 amp flows through the \[2\Omega \] resistor shown in the circuit. The power dissipated in the \[5-\Omega \]resistor is:
  A)
  4 watt done clear
  B)
  2 watt done clear
  C)
  1 watt done clear
  D)
  5 watt done clear
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• question_answer79)
  A electric tea kettle has two heating coils. When first coil of resistance \[{{R}_{1}}\]is switched on, the kettle begins to boil tea in 6 minutes. When second coil of resistance \[{{R}_{2}}\]is switched on, the boiling begins in 8 minutes. The value of \[{{R}_{1}}/{{R}_{2}}\]is
  A)
  \[\frac{7}{3}\] done clear
  B)
  \[\frac{3}{7}\] done clear
  C)
  \[\frac{3}{4}\] done clear
  D)
  \[\frac{4}{3}\] done clear
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• question_answer80)
  An electric fan and a heater are marked as 100 W, 220 V and 1000 W, 220 V respectively. The resistance of heater is     
  A)
  equal to that of fan         done clear
  B)
  lesser than that of fan done clear
  C)
  greater than that of fan done clear
  D)
  zero done clear
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• question_answer81)
  Water boils in the electric kettle in 15 minutes after switching on. If the length of heating wire is decreased to 2/3 of its initial value, then the same amount of water will boil with the same supply voltage in
  A)
  8 minutes done clear
  B)
  10 minutes done clear
  C)
  12 minutes done clear
  D)
  15 minutes done clear
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• question_answer82)
  A wire of radius r and another wire of radius 2r, both of same material and length are connected in series to each other. The combination is connected across a battery. The ratio of the heats produced in the two wires will be
  A)
  4.00 done clear
  B)
  2.00 done clear
  C)
  0.50 done clear
  D)
  0.25 done clear
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• question_answer83)
  A battery of e.m.f. 10 V and internal resistance \[0.5\Omega \]is connected across a variable resistance R. The value of R for which the power delivered in it is maximum is given by
  A)
  \[0.5\Omega \] done clear
  B)
  \[1.0\Omega \] done clear
  C)
  \[2.0\Omega \] done clear
  D)
  \[0.25\Omega \] done clear
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• question_answer84)
  It takes 12 minutes to boil 1 liter of water in an electric kettle. Due to some defect it becomes necessary to remove 20% turns of heating coil of the kettle. After repair, how much time will it take to boil 1 liter of water?
  A)
  9.6 minute         done clear
  B)
         14.4 minute done clear
  C)
  16.8 minute       done clear
  D)
         18.2 minute done clear
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• question_answer85)
  For maximum power from battery the internal resistance of battery r is
  A)
  \[10R\]   done clear
  B)
  \[\frac{4R}{9}\] done clear
  C)
  \[\frac{R}{8}\] done clear
  D)
  \[\frac{10R}{9}\] done clear
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• question_answer86)
  Two cities are 150 km apart. Electric power is sent from one city to another city through copper wires. The fall of potential per km is 8 volt and the average resistance per km is \[0.5\Omega \]. The power loss in the wires is:
  A)
  19.2 W done clear
  B)
  19.2 kW done clear
  C)
  19.2 J done clear
  D)
  12.2 kW done clear
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• question_answer87)
  The charge flowing through a resistance R varies with time t as \[Q=at-b{{t}^{2}}.\] The total heat produced in R by the time current ceases is
  A)
  \[{{a}^{3}}R/6b\] done clear
  B)
  \[{{a}^{3}}R/3b\] done clear
  C)
  \[\frac{{{a}^{3}}R}{2b}\] done clear
  D)
  \[\frac{{{a}^{3}}R}{b}\] done clear
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• question_answer88)
  In a Wheatstone bridge all the four arms have equal resistance R. If the resistance of galvanometer arm is also R, the equivalent resistance of combination is
  A)
  2R done clear
  B)
  R/4 done clear
  C)
  R/2 done clear
  D)
  R done clear
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• question_answer89)
  The resistance of the four arms P, Q, R and S in a Wheatstone?s bridge are 10 ohm, 30 ohm, 30 ohm and 90 ohm, respectively. The e.m.f. and internal resistance of the cell are 7 volt and 5 ohm respectively. If the galvanometer. If the galvanometer resistance is 50 ohm, the current drawn from the cell will be
  A)
  0.2 A    done clear
  B)
  0.1 A done clear
  C)
  2.0 A    done clear
  D)
         1.0 A done clear
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• question_answer90)
  In a Wheatstone?s bridge, three resistance P, Q and R connected in the three arms and the fourth arm is formed by two resistances \[{{S}_{1}}\] and \[{{S}_{2}}\]connected in parallel. The condition for the bridge to be balanced will be
  A)
  \[\frac{P}{Q}=\frac{2R}{{{S}_{1}}+{{S}_{2}}}\] done clear
  B)
  \[\frac{P}{Q}=\frac{R\left( {{S}_{1}}+{{S}_{2}} \right)}{{{S}_{1}}{{S}_{2}}}\] done clear
  C)
  \[\frac{P}{Q}=\frac{R\left( {{S}_{1}}+{{S}_{2}} \right)}{2{{S}_{1}}{{S}_{2}}}\] done clear
  D)
  \[\frac{P}{Q}=\frac{R}{{{S}_{1}}+{{S}_{2}}}\] done clear
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• question_answer91)
  125 cm of potentiometer wire balances the emf of a cell and 100 cm of the wire is required for balance, if the poles of the cell are joined by \[2\Omega \]resistor. Then the internal resistance of the cell is
  A)
  \[0.25\Omega \] done clear
  B)
  \[0.5\Omega \] done clear
  C)
  \[0.75\Omega \] done clear
  D)
  \[1.25\Omega \] done clear
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• question_answer92)
  The resistance of an ammeter is \[13\Omega \]and its scale is graduate for a current upto 100 amps. After an additional shunt has been connected to this ammeter it becomes possible to measure current upto 750 amperes by this meter. The value of shunt-resistance is
  A)
  \[2\Omega \] done clear
  B)
  \[0.2\Omega \] done clear
  C)
  \[2k\Omega \]     done clear
  D)
  \[20\Omega \] done clear
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• question_answer93)
              The resistances in the two arms of the meter bridge are \[5\Omega \] and \[R\Omega \], respectively. When the resistance R is shunted with an equal resistance, the new balance point is at \[1.6{{l}_{1}}.\]The resistance ?R? is:
  A)
  \[10\Omega \] done clear
  B)
  \[15\Omega \] done clear
  C)
  \[20\Omega \] done clear
  D)
  \[25\Omega \] done clear
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• question_answer94)
  In a meter bridge, the balancing length from the left end (standard resistance of one ohm is in the right gap) is found to be 20 cm. The value of the unknown resistance is
  A)
  \[0.8\Omega \]    done clear
  B)
         \[0.5\Omega \] done clear
  C)
  \[0.4\Omega \]    done clear
  D)
         \[0.25\Omega \] done clear
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• question_answer95)
  A potential difference of 220 V is maintained across a 12000 ohm rheostat, as shown in the figure. The voltmeter has a resistance of 6000 ohm and point c is at one-fourth of the distance from a to b, Therefore, the reading of the voltmeter will be
  A)
  32 V                 done clear
  B)
         36 V done clear
  C)
  40 V                             done clear
  D)
  42 V done clear
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• question_answer96)
  In an experiment of potentiometer for measuring the internal resistance of primary cell a balancing length \[\ell \] is obtained on the potentiometer wire when the cell is open circuit. Now the cell is short circuited by a resistance R. If R is to be equal to the internal resistance of the cell the balancing length on the potentiometer wire will be
  A)
  \[\ell \]                           done clear
  B)
  2 \[\ell \] done clear
  C)
  \[\ell \] /2                       done clear
  D)
         \[\ell \] /4 done clear
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• question_answer97)
  The incorrect option in the given circuit if the reading of ammeter is zero is
  A)
  The value of \[{{\varepsilon }_{1}}\]will be \[\frac{\varepsilon \left( R+r \right)}{R}\] done clear
  B)
  Current in R is \[\frac{\varepsilon {{  }_{1}}}{r+R}\] done clear
  C)
  Value of \[\varepsilon {{  }_{1}}\], will be\[\varepsilon  \] done clear
  D)
  Potential across 2R is zero. done clear
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• question_answer98)
  A potentiometer arrangement is shown in fig. The driver cell has emf e and internal resistance r. The resistance of potentiometer wire AB is R. F is the cell of em e/3 and internal resistance r/3. Balance point (J) can be obtained for all finite values of
  A)
  R>r/2 done clear
  B)
  R<r/2 done clear
  C)
  R>r/3 done clear
  D)
  R<r/3 done clear
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• question_answer99)
  In the figure ammeter \[{{A}_{1}}\]reads a current of 10mA, while the voltmeter reads a potential difference of 3V. What does ammeter \[{{A}_{2}}\]in mA read? The ammeters are identical, the internal resistance of the battery is negligible. (Consider all ammeters and voltmeters as non- ideal.)            
  A)
  6.67mA    done clear
  B)
  3.12mA    done clear
  C)
  1.12mA done clear
  D)
  5.14mA done clear
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• question_answer100)
  A battery of emf \[{{E}_{0}}=6V\] is connected across a 2m long uniform wire having resistance \[4\Omega /m.\] The cell of small emf \[{{\varepsilon }_{1}}=2V\] and \[{{\varepsilon }_{2}}=3V\] having internal resistance \[2\Omega \,\And \,1\Omega \] respectively are connected as show in the figure. The null point will be obtained at                        
  A)
  0.10m done clear
  B)
  0.25m done clear
  C)
  0.50m done clear
  D)
  0.75m done clear
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