12th Class Physics Magnetism Question Bank

done Case Based (MCQs) - Moving Charges and Magnetism Total Questions - 50

• question_answer1)

  Direction: Q.1 to Q.5

  In 1820, A Danish physicist, Hans Christian Oersted, discovered that there is a relationship between electricity and magnetism. By setting up a compass through a wire carrying an electric current. Oersted showed that moving electrons can create a magnetic field. Oersted found that, for a straight wire carrying a steady current (DC), the magnetic field lines encircle the current-carrying wire. The magnetic field lines lie in a plane perpendicular to the wire. If the direction of the current is reversed, the direction of the magnetic force reverses. The strength of the field is directly proportional to the magnitude of the current. The strength of the field at any point is inversely proportional to the distance of the point from the wire.

  Read the given passage carefully and give the answer of the following questions.

  Who was the first to discover the relation between electric and magnetid field?
  A)
  H.C. Oersted          done clear
  B)
  Charles William Oersted   done clear
  C)
  Charles Maxwell      done clear
  D)
  Andre Marie Ampere done clear
  View Solution play_arrow

• question_answer2)
            If magnitude of the current in the wire increases, strength of magnetid field:
  A)
  increases   done clear
  B)
  decreases                   done clear
  C)
  remains unchanged   done clear
  D)
  None of these                done clear
  View Solution play_arrow

• question_answer3)
                                   Which of the following statements is true?
  A)
  There is no relationship between electricity and magnetism done clear
  B)
  An electric current produces a magnetid field done clear
  C)
  A compass is not affected by electricity done clear
  D)
  A compass is not affected by a magnet done clear
  View Solution play_arrow

• question_answer4)
  A compass needle is placed below a straight conducting wire. If current is passing through the conducting wire from north to south, then the deflection of the compass is:
  A)
  towards west                  done clear
  B)
  towards east done clear
  C)
  keeps oscillating in east-west direction done clear
  D)
  no deflection done clear
  View Solution play_arrow

• question_answer5)
  Charges at rest can produce:
  A)
  static electric field            done clear
  B)
  magnetic field done clear
  C)
  induced current               done clear
  D)
  conventional current done clear
  View Solution play_arrow

• question_answer6)

  Direction: Q.6 to Q.10

  A charged particle moving in a magnetic field experiences a force that is proportional to the strength of the magnetic field, the component of the velocity that is perpendicular to the magnetic field and the charge of the particle.

  This force is given by \[\overrightarrow{F}=q(\overrightarrow{v}\times \overrightarrow{B})\]where q is the electric charge of the particle, v is the instantaneous velocity of the particle, and B is the magnetic field (in Tesla).

  The direction of force is determined by the rules of cross product of two vectors.

  Force is perpendicular to both velocity and magnetic field.

  Its direction is same as \[\overrightarrow{v}\times \overrightarrow{B}\] if q is positive and opposite to \[\overrightarrow{v}\times \overrightarrow{B}\] if q is negative.

  The force is always perpendicular to both the velocity of the particle and the magnetic field that created it. Because the magnetic force is always perpendicular to the motion, the magnetic field can do no work on an isolated charge. It can only do work indirectly, via the electric field. generated by a changing magnetic field.

  Read the given passage carefully and give the answer of the following questions.

  When a magnetic field is applied on a stationary electron, it:
  A)
  remains stationary         done clear
  B)
  spins about its own axis done clear
  C)
  moves in the direction of the field                       done clear
  D)
  moves perpendicular to the direction of the field. done clear
  View Solution play_arrow

• question_answer7)
  A proton is projected with a uniform velocity v along the axis of a current carrying solenoid, then:
  A)
  the proton will be accelerated along the axis done clear
  B)
  the proton path will be circular about the axis            done clear
  C)
  the proton moves along helical path                  done clear
  D)
  the proton will continue to move with velocity v along the axis.           done clear
  View Solution play_arrow

• question_answer8)
  A charged particle experiences magnetic force in the presence of magnetic field. Which of the following statement is correct?
  A)
  The particle is stationary and magnetid field is perpendicular.    done clear
  B)
  The particle is moving and magnetic field is perpendicular to the velocity. done clear
  C)
  The particle is stationary and magnetic field is parallel. done clear
  D)
  The particle is moving and magnetic field is parallel to velocity.                                                   done clear
  View Solution play_arrow

• question_answer9)
      A charge q moves with a velocity \[2\text{ }m{{s}^{-1}}\] along X-axis in a uniform magnetic field\[\overrightarrow{B}=(\widehat{i}+2\widehat{j}+3\widehat{k})T\], then charge will experience a force:
  A)
  in ZY-plane                    done clear
  B)
  along -Y axis             done clear
  C)
       along + Z axis                done clear
  D)
  along-Z axis                 done clear
  View Solution play_arrow

• question_answer10)
  Moving charge will produce:
  A)
  electric field only done clear
  B)
  magnetic field only done clear
  C)
  both electric and magnetic field done clear
  D)
  None of the above done clear
  View Solution play_arrow

• question_answer11)

  Direction: Q.11 to Q.15

  An electron with speed \[{{v}_{0}}<<c\]moves in a circle of radius \[{{r}_{0}}\] in a uniform magnetic field,

  This electron is able to traverse a circular path as magnetic field is perpendicular to the velocity of the electron. A force acts on the particle perpendicular to both \[\overrightarrow{{{v}_{0}}}\] and \[\overrightarrow{B}\]. This force continuously deflects the particle sideways without changing its speed and the particle will move along a circle perpendicular to the field. The time required for one revolution of the electron is \[{{T}_{0}}\] .

  Read the given passage carefully and give the answer of the following questions.

  If the speed of the electron is now doubled to \[2{{v}_{0}}\]. The radius of the circle will change to:
  A)
  \[4{{r}_{0}}\]                           done clear
  B)
  \[2{{r}_{0}}\]       done clear
  C)
  \[{{r}_{0}}\]                             done clear
  D)
  \[{{r}_{0}}/2\] done clear
  View Solution play_arrow

• question_answer12)
  If \[v=2{{v}_{0}}\], then the time required for one revolution of the electron will change to:
  A)
  \[4{{T}_{0}}\]                          done clear
  B)
  \[2{{T}_{0}}\] done clear
  C)
  \[{{T}_{0}}\]                            done clear
  D)
  \[{{T}_{0}}/2\] done clear
  View Solution play_arrow

• question_answer13)
  A charged particle is projected in a magnetic field\[\overrightarrow{B}=(2\widehat{i}+4\widehat{j})\times {{10}^{2}}T\]. The acceleration of the particle is found to be \[\overrightarrow{a}=(x\widehat{i}+2\widehat{j})m{{s}^{-2}}\]. Find the value of x.
  A)
      \[4\,m{{s}^{-2}}\]                    done clear
  B)
  \[-4\,m{{s}^{-2}}\] done clear
  C)
              \[-2\,m{{s}^{-2}}\]       done clear
  D)
              \[2\,m{{s}^{-2}}\] done clear
  View Solution play_arrow

• question_answer14)
  If the given electron has a velocity not perpendicular to B, then trajectory of the electron is:
  A)
  straight line                    done clear
  B)
  circular done clear
  C)
  helical                           done clear
  D)
  zig-zag          done clear
  View Solution play_arrow

• question_answer15)
  If this electron of charge (e) is moving parallel to uniform magnetic field with constant velocity v. the force acting on the electron is:
  A)
  Bev done clear
  B)
  \[\frac{Be}{v}\] done clear
  C)
  \[\frac{B}{ev}\]                         done clear
  D)
  zero done clear
  View Solution play_arrow

• question_answer16)

  Direction: Q.16 to Q.20

  The path of a charged particle in magnetic field depends upon angle between velocity and magnetic field.

  If velocity \[\overrightarrow{v}\] is at angle \[\theta \] to \[\overrightarrow{B}\], component of velocity parallel to magnetic field \[(v\,cos\,\theta )\] is responsible for circular motion, thus the charge particle moves in a helical path.                                                     .

  The plane of the circle is perpendicular to the magnetic field and the axis of the helix is parallel to the magnetic field. The charged particle moves along helical path touching the line parallel to the magnetic field passing through the starting point after each rotation.

  Radius of circular path is \[r=\frac{mv\,\sin \theta }{qB}\]

  Hence the resultant path of the charged particle will be a helix, with its axis along the direction of \[\overrightarrow{B}\] as shown in figure.

  Read the given passage carefully and give the answer of the following questions.

                                 When a positively charged particle enters into a uniform magnetic field with uniform velocity, its trajectory can be (i) a straight line (ii) a circle (iii) a helix.
  A)
  (i) only                          done clear
  B)
  (i) or (ii)                     done clear
  C)
           (i) or (iii)                        done clear
  D)
  any one of (i) (ii) and (iii)        done clear
  View Solution play_arrow

• question_answer17)
  Two charged particles A and B having the same charge, mass and speed enter into a magnetic field in such a way that the initial path of A makes an angle of \[30{}^\circ \] and that of B makes an angle of \[90{}^\circ \] with the field. Then the trajectory of:
  A)
  B will have smaller radius of curvature than that of A done clear
  B)
  both will have the same curvature done clear
  C)
  A will have smaller radius of curvature than that of B done clear
  D)
  both will move along the direction of their original velocities. done clear
  View Solution play_arrow

• question_answer18)
  An electron having momentum \[2.4\times {{10}^{-23}}kg\text{ }m/s\]enters a region of uniform magnetic field of 0.15 T. The field vector makes an angle of \[30{}^\circ \] with the initial velocity vector of the electron. The radius of the helical path of the electron in the field shall be:    
  A)
  2 mm                            done clear
  B)
  1mm    done clear
  C)
  \[\frac{\sqrt{3}}{2}mm\]                        done clear
  D)
  0.5 mm done clear
  View Solution play_arrow

• question_answer19)
  The magnetic field in a certain region of space is given by \[\overrightarrow{B}=8.35\times {{10}^{-2}}\widehat{i}\,\,T\]. A proton shot into the field with velocity \[\overrightarrow{v}=(2\times {{10}^{5}}\widehat{i}+4\times {{10}^{2}}\widehat{j})m/s\]. The proton follows a helical path in the field. The distance moved by proton in the x-direction during the period of one revolution in the yz-plane will be (Mass proton \[=1.67\times {{10}^{-27}}kg\]):
  A)
  0.053 m                        done clear
  B)
  0.136 m done clear
  C)
  0.157 m                        done clear
  D)
  0.236 m done clear
  View Solution play_arrow

• question_answer20)
  The frequency of revolution of the particle is:
  A)
              \[\frac{m}{qB}\]                                  done clear
  B)
  \[\frac{qB}{2\pi m}\]      done clear
  C)
              \[\frac{2\pi R}{v\,\cos \theta }\]   done clear
  D)
              \[\frac{2\pi R}{v\,sin\theta }\] done clear
  View Solution play_arrow

• question_answer21)

  Direction: Q.21 to Q.25

  A magnetic field can be produced by moving, charges or electric currents. The basic equation governing the magnetic field due to a current distribution is the Biot-Savart law.

  Finding the magnetic field resulting from a current distribution involves the vector product, and is inherently a calculus problem when the distance from the current to the field point is continuously chaning.

  According to this law, the magnetic field at a point due to a current element of length \[d\,\overrightarrow{l}\] carrying current I, at a distance r from the element is \[dB=\frac{{{\mu }_{0}}}{4\pi }\frac{I(d\,\overrightarrow{l}\times \overrightarrow{r})}{{{r}^{3}}}\].

  Biot-Savart law has certain similarities as well as difference with Coloumb's law for electrostatic field e. g., there is an angle dependence in Biot-Savart law which is not present in electrostatic case.

  Read the given passage carefully and give the answer of the following questions.

  The direction of magnetic field \[d\overrightarrow{B}\] due to a current element \[Id\text{ }\overrightarrow{l}\] at a point of distance \[\overrightarrow{r}\]from it, when a current \[l\] passes through a long conductor is in the direction:
  A)
  of position vector \[\overrightarrow{r}\] of the point                         done clear
  B)
  of current element \[d\text{ }\overrightarrow{l}\] done clear
  C)
  perpendicular to both \[d\text{ }\overrightarrow{\text{l}}\] and \[\overrightarrow{r}\] done clear
  D)
  perpendicular to \[d\text{ }\overrightarrow{\text{l}}\] only done clear
  View Solution play_arrow

• question_answer22)
                  The magnetic field due to a current in a straight wire segment of length L at a point on its perpendicular bisector at a distance r (r > > L):
  A)
  decreasea as \[\frac{1}{r}\] done clear
  B)
  decreases as \[\frac{1}{{{r}^{2}}}\] done clear
  C)
  decreases as \[\frac{1}{{{r}^{3}}}\]       done clear
  D)
  approaches a finite limit as \[r\to \infty \] done clear
  View Solution play_arrow

• question_answer23)
  Two long straight wires are set parallel to each other. Each carries a current i in the same direction and the separation between them is 2r. The intensity of the magnetic field midway between them is:
  A)
              \[{{\mu }_{0}}i/r\]                   done clear
  B)
  \[4{{\mu }_{0}}i/r\] done clear
  C)
              zero                   done clear
  D)
              \[{{\mu }_{0}}i/4r\] done clear
  View Solution play_arrow

• question_answer24)
  A long straight wire carries a current along the z-axis for any two points in the x-y plane. Which of the following is always false?
  A)
  The magnetic fields are equal done clear
  B)
  The directions of the magnetic fields are the same done clear
  C)
  The magnitudes of the magnetic fields are equal done clear
  D)
  The field at one point is opposite to that at the other point done clear
  View Solution play_arrow

• question_answer25)
  Biot-Savart law can be expressed alternatively as:
  A)
  Coulomb's Law               done clear
  B)
  Ampere's circuital law done clear
  C)
  Ohm's Law           done clear
  D)
  Gauss's Law done clear
  View Solution play_arrow

• question_answer26)

  Direction: Q.26 to Q.30

  Ampere's law gives a method to calculate the magnetic field due   to   given   current     distribution. According to it, the circulation \[\oint{\overrightarrow{B}\cdot d\,\overrightarrow{l}}\] of the resultant magnetic field along a

  closed plane curve is equal to \[{{\mu }_{0}}\] times the total current crossing the area bounded by the closed curve provided the electric field inside the loop remains constant. Ampere's law is more useful under certain symmetrical conditions. Consider one such case of a long straight wire with circular cross-section (radius R) carrying current I uniformly distributed across this cross-section.

  Read the given passage carefully and give the answer of the following questions.

  The magnetic field at a radial distance r from the centre of the wire in the region r > R, is:
  A)
              \[\frac{{{\mu }_{0}}l}{2\pi r}\]                                   done clear
  B)
  \[\frac{{{\mu }_{0}}l}{2\pi R}\] done clear
  C)
              \[\frac{{{\mu }_{0}}l{{R}^{2}}}{2\pi r}\]         done clear
  D)
              \[\frac{{{\mu }_{0}}l{{r}^{2}}}{2\pi R}\] done clear
  View Solution play_arrow

• question_answer27)
  The magnetic field at a distance r in the region r<R is:
  A)
      \[\frac{{{\mu }_{0}}l}{2\pi }\]                           done clear
  B)
  \[\frac{{{\mu }_{0}}l{{r}^{2}}}{2\pi {{R}^{2}}}\] done clear
  C)
              \[\frac{{{\mu }_{0}}l}{2\pi r}\]              done clear
  D)
              \[\frac{{{\mu }_{0}}lr}{2\pi {{R}^{2}}}\] done clear
  View Solution play_arrow

• question_answer28)
  A long straight wire of a circular cross section (radius a) carries a steady current l and the current l is uniformly distributed across this cross-section. Which of the following plots represents the variation of magnitude of magnetic field B with distance r from the centre of the wire?
  A)
             done clear
  B)
              done clear
  C)
  done clear
  D)
  done clear
  View Solution play_arrow

• question_answer29)
  A long straight wire of radius R carries a steady current l. The current is uniformly distributed across its cross-section. The ratio of magnetic field at R/2 and 2R is:
  A)
  \[\frac{1}{2}\]   done clear
  B)
              2 done clear
  C)
              \[\frac{1}{4}\]                           done clear
  D)
              1 done clear
  View Solution play_arrow

• question_answer30)
  A direct current l flows along the length of an infinitely long straight thin walled pipe, then the magnetic field is:
  A)
  uniform throughout the pipe but not zero done clear
  B)
              zero only along the axis of the pipe done clear
  C)
              zero at any point inside the pipe done clear
  D)
              maximum at the centre and minimum at the edges. done clear
  View Solution play_arrow

• question_answer31)

  Direction: Q.31 to Q.35

  As shown in figure a solenoid where the wire is coiled around a cylinder, each wire loop in this coil acts as if it was a separate circular wire carrying the same current l, the current in the coiled wire and the dense enough array of such loops may be approximated by a cylindrical current sheet with the current density.

  \[J=I\times (N/L)=I\times L\,\,(loops/solenoid\,\,length)\]

  For simplicity, let's assume a long solenoid (length >> diameter) which we approximate as infinitely long. For a long solenoid (compared to its diameter), the magnetic field inside the solenoid is approximately uniform and approximately parallel to the axis, except near the ends of the solenoid. Outside the solenoid, the magnetic field looks like the field of a physical dipole, with the north pole at one end of the solenoid and the south pole at the other end and is approximately negligible.

  Read the given passage carefully and give the answer of the following questions.

  Which of the following material can be used to make loops around the cylinder?
  A)
  Plastic                           done clear
  B)
              Glass    done clear
  C)
              Quartz                           done clear
  D)
              Copper done clear
  View Solution play_arrow

• question_answer32)
  The magnetic field inside the solenoid is:
  A)
  non-uniform and parallel to the axis done clear
  B)
              uniform and parallel to the axis done clear
  C)
              non-uniform and perpendicular to the axis done clear
  D)
              uniform and perpendicular to the axis done clear
  View Solution play_arrow

• question_answer33)
  A proton is moving from left to right direction and outside the solenoid, then what is the direction of force on the proton?
  A)
  Upwards                        done clear
  B)
              Downwards done clear
  C)
              Proton will not deflect done clear
  D)
              Inwards done clear
  View Solution play_arrow

• question_answer34)
  How the magnetic field inside the solenoid depends upon the number of turns?
  A)
  Inversely proportional done clear
  B)
              Directly proportional done clear
  C)
              Proportional to the number of turns done clear
  D)
              None of the above done clear
  View Solution play_arrow

• question_answer35)
  Direction of magnetic field in a solenoid can be determined by:
  A)
  Ohm's Law              done clear
  B)
              Fleming's left-hand rule done clear
  C)
              Ampere's right-hand rule done clear
  D)
              Biot-Savart's Law done clear
  View Solution play_arrow

• question_answer36)

  Direction: Q.36 to Q.40

  A solenoid is a long coil of wire tightly wound in the helical form. Solenoid consists of closely stacked rings electrically insulated from each other wrapped around a non-conducting cylinder.

  Figure below shows the magnetic field lines of a solenoid carrying a steady current I. We see that if the turns are closely spaced, the resulting magnetic field inside the solenoid becomes fairly uniform, provided that the length of the solenoid is much greater than its diameter. For an "ideal" solenoid, which is infinitely long with turns thighly packed, the magnetic field inside the solenoid is uniform and parallel to the axis, and vanishes outside the solenoid.

  Read the given passage carefully and give the answer of the following questions.

                                 A Long solenoid has 800 turns per metre length of solenoid. A current of 1.6 A flows through it. The magnetic induction at the end of the solenoid on its axis is:
  A)
              \[16\times {{10}^{-4}}T\]                  done clear
  B)
              \[8\times {{10}^{-4}}T\] done clear
  C)
                          \[32\times {{10}^{-4}}T\]         done clear
  D)
  \[4\times {{10}^{-4}}T\] done clear
  View Solution play_arrow

• question_answer37)
  Choose the correct statement in the following:
  A)
  The magnetic field inside the solenoid is less than that of outside                                               done clear
  B)
              The magnetic field inside an ideal solenoid is not at all uniform   done clear
  C)
              The magnetic field at the centre, inside an ideal solenoid is almost twice that at the ends done clear
  D)
              The magnetic field at the centre, inside an ideal solenoid is almost half of that at the ends done clear
  View Solution play_arrow

• question_answer38)
  The magnetic field (B) inside a Long solenoid having n turns per unit length and carrying current l when iron core is kept in it is (\[{{\mu }_{0}}\] = permeability of vacuum, \[\chi \] = magnetic susceptibility):
  A)
      \[{{\mu }_{0}}nl(1-\chi )\] done clear
  B)
              \[{{\mu }_{0}}nl\,\chi \] done clear
  C)
                          \[{{\mu }_{0}}n{{l}^{2}}(1+\chi )\]     done clear
  D)
  \[{{\mu }_{0}}nl(1+\chi )\] done clear
  View Solution play_arrow

• question_answer39)
  A solenoid of length l and having n turns carries a current l is in anticlockwise direction. The magnetic field is:
  A)
              \[{{\mu }_{0}}nl\] done clear
  B)
                          \[{{\mu }_{0}}\frac{nl}{{{l}^{2}}}\] done clear
  C)
              along the axis of solenoid done clear
  D)
              perpendicular to the axis of coil done clear
  View Solution play_arrow

• question_answer40)
  The magnitude of the magnetic field inside a long solenoid is increased by:
  A)
  decreasing its radius done clear
  B)
              decreasing the current through it done clear
  C)
              increasing its area of cross-section done clear
  D)
              introducing a medium of higher permeability done clear
  View Solution play_arrow

• question_answer41)

  Direction: Q.41 to Q.45

  When a rectangular loop PQRS of sides 'a' and 'b’ carrying current I is placed in uniform magnetic

  field \[\overrightarrow{B}\], such that area vector \[\overrightarrow{A}\] makes an angle \[\theta \] with direction of magnetic field, then forces on the arms QR and SP of loop are equal,          opposite and collinear, thereby perfectly cancel each other, whereas forces on the arms PQ and RS of loop are equal and opposite but not collinear, so they give rise to torque on the loop.

  Force on side PQ or RS of loop is \[F=lbB\,\sin \,90{}^\circ =lbB\] and perpendicular distance between two non-collinear forces is \[{{r}_{\bot }}=a\,\sin \,\theta \]

  So, torque on the loop, \[\tau =JAB\,\sin \theta \]

  In vector form, torque \[\tau =\overrightarrow{M}\times \overrightarrow{B}\]

  where \[\overrightarrow{M}\times NI\,\overrightarrow{A}\] is called magnetic dipole moment of current loop and is directed in direction of area vector \[\overrightarrow{A}\] i.e., normal to the plane of loop.

  Read the given passage carefully and give the answer of the following questions.

                                  A circular loop of area \[1\text{ }c{{m}^{2}}\], carrying a current of 10 A is placed in a magnetic field of 0.1 T perpendicular to the plane of the loop. The torque on the loop due to the magnetic field is:
  A)
  zero done clear
  B)
                                      \[{{10}^{-4}}Nm\] done clear
  C)
              \[~{{10}^{-2}}Nm\]                done clear
  D)
              1 N m done clear
  View Solution play_arrow

• question_answer42)
       Relation between magnetic moment and angular velocity is:
  A)
              \[M\propto \omega \]                done clear
  B)
              \[M\propto {{\omega }^{2}}\] done clear
  C)
                          \[M\propto \sqrt{\omega }\]          done clear
  D)
  None of these done clear
  View Solution play_arrow

• question_answer43)
  A current Loop in a magnetic field:
  A)
  can be a equilibrium in two orientations, both the equilibrium states are unstable  done clear
  B)
                   can be in equilibrium in two orientations, one stable while the other is unstable      done clear
  C)
              experiences a torque whether the field is uniform or non uniform in all orientations done clear
  D)
              can be in equilibrium in one orientation done clear
  View Solution play_arrow

• question_answer44)
                                     Q.4.     The magnetic moment of a current l carrying circular coil of radius r and number of turns N varies as:
  A)
      \[\frac{1}{{{r}^{2}}}\] done clear
  B)
              \[\frac{1}{r}\] done clear
  C)
              r                       done clear
  D)
  \[{{r}^{2}}\] done clear
  View Solution play_arrow

• question_answer45)
  A rectangular coil carrying current is placed in a non-uniform magnetic field. On that coil the total:
  A)
  force is non-zero              done clear
  B)
              force is zero done clear
  C)
              torque is zero                  done clear
  D)
              None of these                 done clear
  View Solution play_arrow

• question_answer46)
                                      

  Direction: Q.46 to Q.50

  Moving coil galvanometer operates on Permanent Magnet Moving Coil (PMMC) mechanism and was designed by the scientist D'arsonval.

  Moving coil galvanometers are of two types:

  (i) Suspended coil

  (ii) Pivoted coil type or tangent galvanometer.

  Its working is based on the fact that when a current carrying coil is placed in a magnetic     field, it experiences a torque. This torque tends to rotate the coil about its axis of suspension in such a way that the magnetic flux passing through the coil is maximum.

  Read the given passage carefully and give the answer of the following questions.

  A moving coil galvanometer is an instrument which:
  A)
  is used to measure emf done clear
  B)
              is used to measure potential difference done clear
  C)
              is used to measure resistance done clear
  D)
              is a deflection instrument which gives a deflection when a current flows through its coil done clear
  View Solution play_arrow

• question_answer47)
  To make the field radial in a moving coil galvanometer.
  A)
  number of turns of coil is kept small done clear
  B)
              magnet is taken in the form of horse-shoe done clear
  C)
              poles are of very strong magnets done clear
  D)
              poles are cylindrically cut done clear
  View Solution play_arrow

• question_answer48)
  The deflection in a moving coil galvanometer is:
  A)
  directly proportional to torsional constant of spring done clear
  B)
              directly proportional to the number of turns in the coil done clear
  C)
              inversely proportional to the area of the coil done clear
  D)
              inversely proportional to the current in the coil done clear
  View Solution play_arrow

• question_answer49)
  In a moving coil galvanometer, having a coil of N-turns of area A and carrying current l is placed in a radial field of strength B.
  A)
      \[N{{A}^{2}}{{B}^{2}}l\]                  done clear
  B)
              \[NAB{{l}^{2}}\] done clear
  C)
                          \[{{N}^{2}}ABl\]         done clear
  D)
  \[NABl\] done clear
  View Solution play_arrow

• question_answer50)
  To increase the current sensitivity of a moving coil galvanometer, we should decrease:
  A)
  (a) strength of magnet   done clear
  B)
              (b) torsional constant of spring done clear
  C)
              number of turns in coil done clear
  D)
              area of coil done clear
  View Solution play_arrow