JEE Main & Advanced Physics Electro Magnetic Induction Question Bank

done Faraday's and Lenz's Law Total Questions - 68

• question_answer1)
  In electromagnetic induction, the induced e.m.f. in a coil is independent of                                         [CPMT 1984]
  A)
  Change in the flux                          done clear
  B)
  Time          done clear
  C)
  Resistance of the circuit              done clear
  D)
  None of the above done clear
  View Solution play_arrow

• question_answer2)
  Lenz's law is consequence of the law of conservation of [JIPMER 1997; CPMT 1990; RPMT 1997; MP PET 1999; MP PMT 2000, 03; RPET 2003; AFMC 2004]
  A)
             Charge                                     done clear
  B)
             Momentum done clear
  C)
             Mass                                        done clear
  D)
             Energy done clear
  View Solution play_arrow

• question_answer3)
  In electromagnetic induction, the induced charge in a coil is independent of
  A)
             Change in the flux              done clear
  B)
             Time done clear
  C)
             Resistance in the circuit    done clear
  D)
             None of the above done clear
  View Solution play_arrow

• question_answer4)
  The magnetic flux through a circuit of resistance \[R\] changes by an amount \[\Delta \varphi \] in time \[\Delta t\],  Then the total quantity of electric charge \[Q\], which passing during this time through any point of the circuit is given by [Haryana CEE 1996; CBSE PMT 2004]
  A)
             \[Q=\frac{\Delta \varphi }{\Delta t}\]                            done clear
  B)
             \[Q=\frac{\Delta \varphi }{\Delta t}\times R\] done clear
  C)
             \[Q=-\frac{\Delta \varphi }{\Delta t}+R\]                     done clear
  D)
             \[Q=\frac{\Delta \varphi }{R}\] done clear
  View Solution play_arrow

• question_answer5)
  A cylindrical bar magnet is kept along the axis of a circular coil. If the magnet is rotated about its axis, then                                                                [CPMT 1983; BCECE 2004]
  A)
              A current will be induced in a coil done clear
  B)
              No current will be induced in a coil done clear
  C)
              Only an e.m.f. will be induced in the coil done clear
  D)
              An e.m.f. and a current both will be induced in the coil done clear
  View Solution play_arrow

• question_answer6)
   A metallic ring is attached with the wall of a room. When the north pole of a magnet is brought near to it, the induced current in the ring will be [AFMC 1993; MP PMT/PET 1998; Pb PET 2003]                                                                                       
  A)
              First clockwise then anticlockwise done clear
  B)
              In clockwise direction done clear
  C)
              In anticlockwise direction done clear
  D)
              First anticlockwise then clockwise done clear
  View Solution play_arrow

• question_answer7)
  A coil having an area \[{{A}_{0}}\] is placed in a magnetic field which changes from \[{{B}_{0}}\]to \[4{{B}_{0}}\] in a time interval t. The e.m.f. induced in the coil will be                                         [MP PET 1990]
  A)
             \[\frac{3{{A}_{0}}{{B}_{0}}}{t}\]                                       done clear
  B)
             \[\frac{4{{A}_{0}}{{B}_{0}}}{t}\] done clear
  C)
             \[\frac{3{{B}_{0}}}{{{A}_{0}}t}\]                                       done clear
  D)
             \[\frac{4{{B}_{0}}}{{{A}_{0}}t}\] done clear
  View Solution play_arrow

• question_answer8)
  The magnetic flux linked with a coil is given by an equation \[\varphi \] (in webers) = \[8{{t}^{2}}+3t+5\]. The induced e.m.f. in the coil at the fourth second will be                                                       [MP PET 1990]
  A)
             16 units                                   done clear
  B)
             39 units done clear
  C)
             67 units                                   done clear
  D)
             145 units done clear
  View Solution play_arrow

• question_answer9)
  The current flowing in two coaxial coils in the same direction. On increasing the distance between the two, the electric current will                                                                  [MP PMT 1991]
  A)
              Increase done clear
  B)
              Decrease done clear
  C)
              Remain unchanged done clear
  D)
              The information is incomplete done clear
  View Solution play_arrow

• question_answer10)
  A copper ring is held horizontally and a bar magnet is dropped through the ring with its length along the axis of the ring. The acceleration of the falling magnet while it is passing through the ring is                  [CBSE PMT 1996; MP PET 1990, 99;                    CPMT 1991, 99; JIPMER 1997; CPMT 2003;                    MP PET/PMT 2001; KCET 2001; Kerala (Engg.) 2001]
  A)
             Equal to that due to gravity done clear
  B)
             Less than that due to gravity done clear
  C)
             More than that due to gravity done clear
  D)
             Depends on the diameter of the ring and the length of the magnet done clear
  View Solution play_arrow

• question_answer11)
  A square coil \[{{10}^{-2}}{{m}^{2}}\] area is placed perpendicular to a uniform magnetic field of intensity \[{{10}^{3}}Wb/{{m}^{2}}\]. The magnetic flux through the coil is                               [MP PMT 1990, 2001]
  A)
             10 weber                                 done clear
  B)
             \[{{10}^{-5}}\]weber done clear
  C)
             \[{{10}^{5}}\]weber           done clear
  D)
             100 weber done clear
  View Solution play_arrow

• question_answer12)
  A magnet is brought towards a coil (i) speedly (ii) slowly then the induced e.m.f./induced charge will be respectively [RPMT 1997; MP PMT 2003]
  A)
              More in first case / More in first case done clear
  B)
              More in first case/Equal in both case done clear
  C)
              Less in first case/More in second case done clear
  D)
              Less in first case/Equal in both case done clear
  View Solution play_arrow

• question_answer13)
  The direction of induced e.m.f. during electromagnetic induction is given by                                       [MP PET 1994, 96]
  A)
             Faraday's law                        done clear
  B)
             Lenz's law done clear
  C)
             Maxwell's law                       done clear
  D)
             Ampere's law done clear
  View Solution play_arrow

• question_answer14)
  In a coil of area \[10\ c{{m}^{2}}\] and 10 turns with a magnetic field directed perpendicular to the plane and is changing at the rate of \[{{10}^{8}}\]gauss/second. The resistance of the coil is 20 ohm. The current in the coil will be         [CPMT 1976]
  A)
             5 amp                                      done clear
  B)
             0.5 amp done clear
  C)
             0.05 amp                                done clear
  D)
             \[5\times {{10}^{8}}\ amp\] done clear
  View Solution play_arrow

• question_answer15)
   As shown in the figure, a magnet is moved with a fast speed towards a coil at rest. Due to this induced electromotive force, induced current and induced charge in the coil is \[E,\ I\] and \[Q\] respectively. If the speed of the magnet is doubled, the incorrect statement is                                                                        [MP PET 1995]
  A)
             \[E\] increases                     done clear
  B)
             \[I\] increases done clear
  C)
             \[Q\] remains same           done clear
  D)
             \[Q\] increases done clear
  View Solution play_arrow

• question_answer16)
  A coil having 500 square loops each of side 10 cm is placed normal to a magnetic flux which increases at the rate of 1.0 tesla/second. The induced e.m.f. in volts is [CPMT 1989, 90; DCE 2002]
  A)
              0.1 done clear
  B)
             0.5 done clear
  C)
              1    done clear
  D)
             5 done clear
  View Solution play_arrow

• question_answer17)
  When a magnet is pushed in and out of a circular coil C connected to a very sensitive galvanometer G as shown in the adjoining diagram with a frequency \[\nu \], then
  A)
             Constant deflection is observed in the galvanometer done clear
  B)
             Visible small oscillations will be observed in the galvanometer if \[\nu \]is about 50 Hz done clear
  C)
             Oscillations in the deflection will be observed clearly if \[\nu =1\] or 2 Hz done clear
  D)
             No variation in the deflection will be seen if \[\nu =1\]or 2 Hz done clear
  View Solution play_arrow

• question_answer18)
  A coil of area \[100c{{m}^{2}}\] has 500 turns. Magnetic field of \[0.1\ weber/metr{{e}^{2}}\] is perpendicular to the coil. The field is reduced to zero in 0.1 second. The induced e.m.f. in the coil is                    [MP PMT 1991; MH CET (Med.) 1999]
  A)
             1 V done clear
  B)
             5 V done clear
  C)
             50 V                                          done clear
  D)
              Zero done clear
  View Solution play_arrow

• question_answer19)
  A 50 turns circular coil has a radius of \[3\ cm\], it is kept in a magnetic field acting normal to the area of the coil. The magnetic field \[B\] increased from 0.10 tesla to 0.35 tesla in 2 milliseconds. The average induced e.m.f. in the coil is [MP PET 1994]
  A)
             \[1.77\ volts\]                       done clear
  B)
             \[17.7\ volts\] done clear
  C)
             \[177\ volts\]                        done clear
  D)
             \[0.177\ volts\] done clear
  View Solution play_arrow

• question_answer20)
  A coil having an area \[2{{m}^{2}}\] is placed in a magnetic field which changes from \[1Wb/{{m}^{2}}\]to \[4Wb/{{m}^{2}}\]in a interval of 2 second. The e.m.f. induced in the coil will be [DPMT 1999; MP PET 2002]
  A)
              4 V                                            done clear
  B)
             3 V done clear
  C)
              1.5 V                                        done clear
  D)
             2 V done clear
  View Solution play_arrow

• question_answer21)
  A coil has 2000 turns and area of\[70c{{m}^{2}}\]. The magnetic field perpendicular to the plane of the coil is \[0.3Wb/{{m}^{2}}\]and takes 0.1sec to rotate through\[{{180}^{o}}\]. The value of the induced e.m.f. will be                        [MP PET 1993; Similar to AIIMS 1997]
  A)
             \[8.4V\]                                   done clear
  B)
             \[84V\] done clear
  C)
             \[42V\]                                    done clear
  D)
             \[4.2V\] done clear
  View Solution play_arrow

• question_answer22)
  Two different loops are concentric and lie in the same plane. The current in the outer loop is clockwise and increasing with time. The induced current in the inner loop then, is [MP PET 1993]
  A)
             Clockwise done clear
  B)
             Zero done clear
  C)
             Counter clockwise done clear
  D)
             In a direction that depends on the ratio of the loop radii done clear
  View Solution play_arrow

• question_answer23)
  According to Faraday's law of electromagnetic induction [MP PET 1994]
  A)
             The direction of induced current is such that it opposes the cause producing it done clear
  B)
             The magnitude of induced e.m.f. produced in a coil is directly proportional to the rate of change of magnetic flux done clear
  C)
             The direction of induced e.m.f. is such that it opposes the cause producing it done clear
  D)
             None of the above done clear
  View Solution play_arrow

• question_answer24)
  The unit of magnetic flux is [MP PMT 1994; MP PET 1995; AFMC 1998]
  A)
             \[Weber/{{m}^{2}}\]         done clear
  B)
             Weber done clear
  C)
             Henry                                       done clear
  D)
             Ampere/m done clear
  View Solution play_arrow

• question_answer25)
  The north pole of a long horizontal bar magnet is being brought closer to a vertical conducting plane along the perpendicular direction. The direction of the induced current in the conducting plane will be                       [MP PMT 1994]
  A)
             Horizontal                              done clear
  B)
             Vertical done clear
  C)
             Clockwise                               done clear
  D)
             Anticlockwise done clear
  View Solution play_arrow

• question_answer26)
  The magnetic field in a coil of 100 turns and 40 square cm area is increased from 1 Tesla to 6 Tesla in 2 second. The magnetic field is perpendicular to the coil. The e.m.f. generated in it is                                   [MP PMT 1994]
  A)
             \[{{10}^{4}}\,V\]                  done clear
  B)
             1.2 V done clear
  C)
             1.0 V                                         done clear
  D)
             \[{{10}^{-2}}\,V\] done clear
  View Solution play_arrow

• question_answer27)
  The dimensions of magnetic flux are [MP PMT 1994; CBSE PMT 1999]
  A)
             \[ML{{T}^{-2}}{{A}^{-2}}\]      done clear
  B)
             \[M{{L}^{2}}{{T}^{-2}}{{A}^{-2}}\] done clear
  C)
             \[M{{L}^{2}}{{T}^{-1}}{{A}^{-2}}\]                                   done clear
  D)
             \[M{{L}^{2}}{{T}^{-2}}{{A}^{-1}}\] done clear
  View Solution play_arrow

• question_answer28)
   Lenz's law gives                                                        [MP PMT 1994]
  A)
             The magnitude of the induced e.m.f. done clear
  B)
             The direction of the induced current done clear
  C)
             Both the magnitude and direction of the induced current done clear
  D)
             The magnitude of the induced current done clear
  View Solution play_arrow

• question_answer29)
  The north pole of a bar magnet is moved swiftly downward towards a closed coil and then second time it is raised upwards slowly. The magnitude and direction of the induced currents in the two cases will be of              [MP PET 1996]                    First case                            Second case
  A)
             Low value clockwise                  Higher value anticlockwise done clear
  B)
             Low value clockwise               Equal value anticlockwise done clear
  C)
             Higher value clockwise           Low value clockwise done clear
  D)
             Higher value anticlockwise   Low value clockwise done clear
  View Solution play_arrow

• question_answer30)
  A metallic ring connected to a rod oscillates freely like a pendulum. If now a magnetic field is applied in horizontal direction so that the pendulum now swings through the field, the pendulum will
  A)
             Keep oscillating with the old time period done clear
  B)
             Keep oscillating with a smaller time period done clear
  C)
             Keep oscillating with a larger time period done clear
  D)
             Come to rest very soon done clear
  View Solution play_arrow

• question_answer31)
  A circular coil of 500 turns of wire has an enclosed area of \[0.1\,{{m}^{2}}\] per turn. It is kept perpendicular to a magnetic field of induction 0.2 T and rotated by 180° about a diameter perpendicular to the field in 0.1 sec. How much charge will pass when the coil is connected to a galvanometer with a combined resistance of 50 ohms                    [MP PET 1997]
  A)
             0.2 C                                         done clear
  B)
             0.4 C done clear
  C)
             2 C  done clear
  D)
             4 C done clear
  View Solution play_arrow

• question_answer32)
  A coil of 100 turns and area 5 square centimetre is placed in a magnetic field B = 0.2 T. The normal to the plane of the coil makes an angle of 60° with the direction of the magnetic field. The magnetic flux linked with the coil is [MP PMT 1997]
  A)
             \[5\times {{10}^{-3}}Wb\]      done clear
  B)
             \[5\times {{10}^{-5}}\,Wb\] done clear
  C)
             \[{{10}^{-2}}\,Wb\]            done clear
  D)
             \[{{10}^{-4}}\,Wb\] done clear
  View Solution play_arrow

• question_answer33)
  In a circuit with a coil of resistance 2 ohms, the magnetic flux changes from 2.0 Wb to 10.0 Wb in 0.2 second. The charge that flows in the coil during this time is [MP PMT 1997]
  A)
             5.0 coulomb                          done clear
  B)
             4.0 coulomb done clear
  C)
             1.0 coulomb                          done clear
  D)
             0.8 coulomb done clear
  View Solution play_arrow

• question_answer34)
  The direction of induced current is such that it opposes the very cause that has produced it. This is the law of [MP PMT/PET 1998]
  A)
             Lenz                                          done clear
  B)
             Faraday done clear
  C)
             Kirchhoff                                done clear
  D)
             Fleming done clear
  View Solution play_arrow

• question_answer35)
  To induce an e.m.f. in a coil, the linking magnetic flux [KCET 1994]
  A)
             Must decrease done clear
  B)
             Can either increase or decrease done clear
  C)
             Must remain constant done clear
  D)
             Must increase done clear
  View Solution play_arrow

• question_answer36)
  A solenoid is 1.5 m long and its inner diameter is 4.0 cm. It has three layers of windings of 1000 turns each and carries a current of 2.0 amperes. The magnetic flux for a cross-section of the solenoid is nearly                                 [AMU 1995]
  A)
             2.5 ´ 10?7 weber                   done clear
  B)
             6.31 ´ 10?6 weber done clear
  C)
             5.2 ´ 10?5 weber                   done clear
  D)
             4.1 ´ 10?5 weber done clear
  View Solution play_arrow

• question_answer37)
  A coil of 40 W resistance has 100 turns and radius 6 mm is connected to ammeter of resistance of 160 ohms. Coil is placed perpendicular to the magnetic field. When coil is taken out of the field, 32 m C charge flows through it. The intensity of magnetic field will be                            [RPET 1997]
  A)
             6.55 T                                       done clear
  B)
             5.66 T done clear
  C)
             0.655 T                                     done clear
  D)
             0.566 T done clear
  View Solution play_arrow

• question_answer38)
  Faraday's laws are consequence of conservation of [CBSE PMT 1993; BHU 2002]
  A)
             Energy done clear
  B)
             Energy and magnetic field done clear
  C)
             Charge done clear
  D)
             Magnetic field done clear
  View Solution play_arrow

• question_answer39)
  A magnetic field of 2 ´ 10? 2 T acts at right angles to a coil of area 100 cm2 with 50 turns. The average emf induced in the coil is 0.1 V, when it is removed from the field in time t. The value of t is [CBSE PMT 1992; CPMT 2001]
  A)
             0.1 sec                                      done clear
  B)
             0.01 sec done clear
  C)
             1 sec                                         done clear
  D)
             20 sec done clear
  View Solution play_arrow

• question_answer40)
  The total charge induced in a conducting loop when it is moved in magnetic field depends on [CBSE PMT 1992; ISM Dhanbad 1994]
  A)
             The rate of change of magnetic flux done clear
  B)
             Initial magnetic flux only done clear
  C)
             The total change in magnetic flux done clear
  D)
             Final magnetic flux only done clear
  View Solution play_arrow

• question_answer41)
  A rectangular coil of 20 turns and area of cross- section  25 sq cm has a resistance of 100 ohm. If a magnetic field which is perpendicular to the plane of the coil changes at the rate of 1000 Tesla per second, the current in the coil is     [CBSE PMT 1992; Very Similar to MHCET 2002; DPMT 2004]
  A)
             1.0 ampere                            done clear
  B)
             50 ampere done clear
  C)
             0.5 ampere                            done clear
  D)
             5.0 ampere done clear
  View Solution play_arrow

• question_answer42)
  The north pole of a magnet is brought near a metallic ring. The direction of the induced current in the ring will be [AIIMS 1999]
  A)
             Clockwise                               done clear
  B)
             Anticlockwise done clear
  C)
             Towards north                     done clear
  D)
             Towards south done clear
  View Solution play_arrow

• question_answer43)
   Lenz?s law applies to                                                      [DCE 1999]
  A)
             Electrostatics done clear
  B)
             Lenses done clear
  C)
             Electro-magnetic induction done clear
  D)
             Cinema slides done clear
  View Solution play_arrow

• question_answer44)
  If a coil of metal wire is kept stationary in a non-uniform magnetic field, then                                      [BHU 2000]
  A)
             An e.m.f. is induced in the coil done clear
  B)
             A current is induced in the coil done clear
  C)
             Neither e.m.f. nor current is induced done clear
  D)
             Both e.m.f. and current is induced done clear
  View Solution play_arrow

• question_answer45)
  The magnetic flux linked with a coil, in webers, is given by the equations \[\varphi =3{{t}^{2}}+4t+9\]. Then the magnitude of induced e.m.f. at t = 2 second will be [KCET 2000; CPMT 2003; MP PET 2005]
  A)
             2 volt                                        done clear
  B)
             4 volt done clear
  C)
             8 volt                                        done clear
  D)
             16 volt done clear
  View Solution play_arrow

• question_answer46)
  A coil has an area of 0.05 m2 and it has 800 turns. It is placed perpendicularly in a magnetic field of strength \[4\times {{10}^{-5}}\,Wb/{{m}^{2}},\] it is rotated through \[{{90}^{o}}\] in 0.1 sec. The average e.m.f. induced in the coil is                    [CPMT 2001]
  A)
             0.056 V                                    done clear
  B)
             0.046 V done clear
  C)
             0.026 V                                    done clear
  D)
             0.016 V done clear
  View Solution play_arrow

• question_answer47)
  A moving conductor coil in a magnetic field produces an induced e.m.f. This is in accordance with [AFMC 1993; MH CET 2001, 03]
  A)
             Amperes law                        done clear
  B)
             Coulomb law done clear
  C)
             Lenz?s law                              done clear
  D)
             Faraday?s law done clear
  View Solution play_arrow

• question_answer48)
  In the diagram shown if a bar magnet is moved along the common axis of two single turn coils A and B in the direction of arrow                                                     [Kerala (Engg.) 2001]
  A)
             Current is induced only in A & not in B done clear
  B)
             Induced currents in A & B are in the same direction done clear
  C)
             Current is induced only in B and not in A done clear
  D)
             Induced currents in A & B are in opposite directions done clear
  View Solution play_arrow

• question_answer49)
  Magnetic flux f (in weber) linked with a closed circuit of resistance 10 ohm varies with time t (in seconds) as                          \[\varphi =5{{t}^{2}}-4t+1\] The induced electromotive force in the circuit at t = 0.2 sec. is                                                     [MP PMT 2001]
  A)
             0.4 volts                                  done clear
  B)
             ? 0.4 volts done clear
  C)
             ? 2.0 volts                               done clear
  D)
             2.0 volts done clear
  View Solution play_arrow

• question_answer50)
  The formula for induced e.m.f. in a coil due to change in magnetic flux through the coil is (here A = area of the coil, B = magnetic field)                                                         [MP PET 2002]
  A)
             \[e=-A.\frac{dB}{dt}\]      done clear
  B)
             \[e=-B.\frac{dA}{dt}\] done clear
  C)
             \[e=-\frac{d}{dt}(A.B)\]   done clear
  D)
             \[e=-\frac{d}{dt}(A\times B)\] done clear
  View Solution play_arrow

• question_answer51)
  Lenz?s law is expressed by the following formula (here e = induced e.m.f., f = magnetic flux in one turn and N = number of turns)                                                        [MP PET 2002]
  A)
             \[e=-\varphi \frac{dN}{dt}\]  done clear
  B)
             \[e=-N\frac{d\varphi }{dt}\] done clear
  C)
             \[e=-\frac{d}{dt}\left( \frac{\varphi }{N} \right)\]    done clear
  D)
             \[e=N\frac{d\varphi }{dt}\] done clear
  View Solution play_arrow

• question_answer52)
   A magnet is dropped down an infinitely long vertical copper tube                                            [KCET 2002]
  A)
             The magnet moves with continuously increasing velocity and ultimately acquires a constant terminal velocity done clear
  B)
             The magnet moves with continuously decreasing velocity and ultimately comes to rest done clear
  C)
             The magnet moves with continuously increasing velocity but constant acceleration done clear
  D)
             The magnet moves with continuously increasing velocity and acceleration done clear
  View Solution play_arrow

• question_answer53)
  An aluminium ring B faces an electromagnet A. The current I through A can be altered                   [Kerala PET 2002]
  A)
             Whether I increases or decreases, B will not experience any force done clear
  B)
             If I decrease, A will repel B done clear
  C)
             If I increases, A will attract B done clear
  D)
             If I increases, A will repel B done clear
  View Solution play_arrow

• question_answer54)
  The magnetic flux linked with a coil at any instant ?t? is given by f = 5t3 ? 100t + 300, the e.m.f. induced in the coil at t = 2 second is                                                                         [KCET 2003]
  A)
             ? 40 V                                       done clear
  B)
             40 V done clear
  C)
             140 V                                        done clear
  D)
             300 V done clear
  View Solution play_arrow

• question_answer55)
  A coil has 1,000 turns and 500 cm2 as its area. The plane of the coil is placed at right angles to a magnetic induction field of \[2\times {{10}^{-5}}\,Wb/{{m}^{2}}\]. The coil is rotated through \[{{180}^{o}}\] in 0.2 seconds. The average e.m.f. induced in the coil, in milli-volts, is                                                                            [EAMCET 2003]
  A)
             5     done clear
  B)
             10 done clear
  C)
             15   done clear
  D)
             20 done clear
  View Solution play_arrow

• question_answer56)
  When a bar magnet falls through a long hollow metal cylinder fixed with its axis vertical, the final acceleration of the magnet is                                                                            [BVP 2003]
  A)
             Equal to zero done clear
  B)
             Less than g done clear
  C)
             Equal to g done clear
  D)
             Equal to g in to beginning and then more than g done clear
  View Solution play_arrow

• question_answer57)
  The magnetic flux linked with a vector area \[\overrightarrow{A}\] in a uniform magnetic field \[\overrightarrow{B}\] is                                                                   [MP PET 2003]
  A)
             \[\overrightarrow{B}\times \overrightarrow{A}\]   done clear
  B)
             AB done clear
  C)
             \[\overrightarrow{B}\cdot \overrightarrow{A}\]      done clear
  D)
             \[\frac{B}{A}\] done clear
  View Solution play_arrow

• question_answer58)
  The magnetic flux linked with a circuit of resistance 100 ohm increases from 10 to 60 webers. The amount of induced charge that flows in the circuit is (in coulomb) [MP PET 2003]
  A)
             0.5 done clear
  B)
             5 done clear
  C)
             50   done clear
  D)
             100 done clear
  View Solution play_arrow

• question_answer59)
  A magnet NS is suspended from a spring and while it oscillates, the magnet moves in and out of the coil C. The coil is connected to a galvanometer G. Then as the magnet oscillates,                                                 [KCET 2004]
  A)
             G shows deflection to the left and right with constant amplitude                   done clear
  B)
             G shows deflection on one side                                       done clear
  C)
             G shows no deflection. done clear
  D)
             G shows deflection to the left and right but the amplitude steadily decreases.        done clear
  View Solution play_arrow

• question_answer60)
  A coil having n turns and resistance R W  is connected with a galvanometer of resistance \[4R\Omega \]. This combination is moved in time t seconds from a magnetic field W1 weber to W2 weber. The induced current in the circuit is [AIEEE 2004]
  A)
             \[-\frac{{{W}_{2}}-{{W}_{1}}}{5\ Rnt}\]                         done clear
  B)
             \[-\frac{n({{W}_{2}}-{{W}_{1}})}{5\ Rt}\] done clear
  C)
             \[-\frac{({{W}_{2}}-{{W}_{1}})}{Rnt}\]                           done clear
  D)
             \[-\frac{n({{W}_{2}}-{{W}_{1}})}{Rt}\]  done clear
  View Solution play_arrow

• question_answer61)
  If a copper ring is moved quickly towards south pole of a powerful stationary bar magnet, then                 [Pb. PMT 2004]
  A)
             Current flows through the copper ring done clear
  B)
             Voltage in the magnet increase done clear
  C)
             Current flows in the magnet done clear
  D)
             Copper ring will get magnetised done clear
  View Solution play_arrow

• question_answer62)
    The magnetic flux linked with coil, in weber is given by the equation, \[\varphi =5{{t}^{2}}+3t+16\]. The induced emf in the coil in the fourth second is                                                              [Pb. PMT 2004]
  A)
             10 V                                          done clear
  B)
             30 V done clear
  C)
             45 V                                          done clear
  D)
             90 V done clear
  View Solution play_arrow

• question_answer63)
  The coil of area 0.1 m2 has 500 turns. After placing the coil in a magnetic field of strength \[4\times {{10}^{-4}}Wb/{{m}^{2}}\], if rotated through 90o in 0.1 s, the average emf induced in the coil is [Pb. PET 2002]
  A)
             0.012 V                                    done clear
  B)
             0.05 V done clear
  C)
             0.1 V                                         done clear
  D)
             0.2 V   done clear
  View Solution play_arrow

• question_answer64)
  Magnetic flux in a circuit containing a coil of resistance \[2\Omega \]changes from 2.0 Wb to 10 Wb in 0.2 sec. The charge passed through the coil in this time is    [DPMT 2003]
  A)
             0.8 C                                         done clear
  B)
             1.0 C done clear
  C)
             5.0 C                                         done clear
  D)
             4.0 C done clear
  View Solution play_arrow

• question_answer65)
  The diagram below shows two coils A and B placed parallel to each other at a very small distance. Coil A is connected to an ac supply. G is a very sensitive galvanometer. When the key is closed                                          [CPMT 1986]
  A)
             Constant deflection will be observed in the galvanometer for 50 Hz supply done clear
  B)
             Visible small variations will be observed in the galvanometer for 50 Hz input done clear
  C)
             Oscillations in the galvanometer may be observed when the input ac voltage has a frequency of 1 to 2 Hz done clear
  D)
             No variation will be observed in the galvanometer even when the input ac voltage is 1 or 2 Hz done clear
  View Solution play_arrow

• question_answer66)
  An infinitely long cylinder is kept parallel to an uniform magnetic field B directed along positive z axis. The direction of induced current as seen from the z axis will be  [IIT-JEE (Screening) 2005]
  A)
             Clockwise of the +ve z axis     done clear
  B)
             Anticlockwise of the +ve z axis done clear
  C)
             Zero done clear
  D)
             Along the magnetic field done clear
  View Solution play_arrow

• question_answer67)
  In a magnetic field of 0.05T, area of a coil changes from \[101\,c{{m}^{2}}\] to \[100\,c{{m}^{2}}\] without changing the resistance which is 2W. The amount of charge that flow during this period is [Orissa PMT 2005]
  A)
             \[2.5\times {{10}^{-6}}\]coulomb                                    done clear
  B)
             \[2\times {{10}^{-6}}\]coulomb done clear
  C)
             \[{{10}^{-6}}\]coulomb     done clear
  D)
             \[8\times {{10}^{-6}}\]coulomb done clear
  View Solution play_arrow

• question_answer68)
  If a coil of 40 turns and area 4.0 cm2 is suddenly removed from a magnetic field, it is observed that a charge of \[2.0\times {{10}^{-4}}C\] flows into the coil. If the resistance of the coil is \[80\Omega \], the magnetic flux density in \[Wb/{{m}^{2}}\] is                       [MP PET 2005]
  A)
             0.5  done clear
  B)
             1.0  done clear
  C)
             1.5               done clear
  D)
             2.0 done clear
  View Solution play_arrow