JEE Main & Advanced Physics Electro Magnetic Induction Question Bank

done Motional EMI Total Questions - 33

• question_answer1)
  A rectangular coil ABCD is rotated anticlockwise with a uniform angular velocity about the axis shown in diagram below. The axis of rotation of the coil as well as the magnetic field B are horizontal. The induced e.m.f. in the coil would be maximum when                                     [Haryana CEE 1996; MP PMT 1992, 94, 99]
  A)
             The plane of the coil is horizontal done clear
  B)
             The plane of the coil makes an angle of 45° with the magnetic field done clear
  C)
             The plane of the coil is at right angles to the magnetic field done clear
  D)
             The plane of the coil makes an angle of 30° with the magnetic field done clear
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• question_answer2)
             A 10 metre wire kept in east-west falling with velocity 5 m/sec perpendicular to the field\[0.3\times {{10}^{-4}}Wb/{{m}^{2}}\].  The induced e.m.f. across the terminal will be            [MP PET 2000]
  A)
              0.15 V                                      done clear
  B)
             1.5 mV done clear
  C)
              1.5 V                                        done clear
  D)
             15.0 V done clear
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• question_answer3)
  An electric potential difference will be induced between the ends of the conductor shown in the diagram, when the conductor moves in the direction [AIIMS 1982; DPMT 2001]
  A)
              P    done clear
  B)
             Q done clear
  C)
              L     done clear
  D)
             M done clear
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• question_answer4)
  Two rails of a railway track insulated from each other and the ground are connected to a milli voltmeter. What is the reading of voltmeter, when a train travels with a speed of 180 km/hr along the track. Given that the vertical component of earth's magnetic field is \[0.2\times {{10}^{-4}}weber/{{m}^{2}}\] and the rails are separated by 1 metre  [IIT 1981; KCET  2001]
  A)
             \[{{10}^{-2}}volt\]               done clear
  B)
             \[{{10}^{-4}}volt\] done clear
  C)
             \[{{10}^{-3}}volt\]               done clear
  D)
             1 volt done clear
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• question_answer5)
  A conductor of 3 m in length is moving perpendicularly to magnetic field of \[{{10}^{-3}}\]tesla with the speed of \[{{10}^{2}}m/s\], then the e.m.f. produced across the ends of conductor will be                                                             [MP PET 1990]
  A)
              0.03 volt                                 done clear
  B)
             0.3 volt done clear
  C)
             \[3\times {{10}^{-3}}volt\]      done clear
  D)
             3 volt done clear
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• question_answer6)
  When a wire loop is rotated in a magnetic field, the direction of induced e.m.f. changes once in each [MP PMT 1991, 04]
  A)
             \[\frac{1}{4}\] revolution done clear
  B)
             \[\frac{1}{2}\] revolution done clear
  C)
             1 revolution                           done clear
  D)
             2 revolution done clear
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• question_answer7)
  An aeroplane in which the distance between the tips of wings is 50 m is flying horizontally with a speed of 360 km/hr over a place where the vertical components of earth magnetic field is\[2.0\times {{10}^{-4}}weber/{{m}^{2}}\]. The potential difference between the tips of wings would be [CPMT 1990; MP PET 1991]
  A)
             0.1 V                                         done clear
  B)
             1.0 V done clear
  C)
             0.2 V                                         done clear
  D)
             0.01 V done clear
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• question_answer8)
  A copper disc of radius 0.1 m is rotated about its centre with 10 revolutions per second in a uniform magnetic field of 0.1 Tesla with its plane perpendicular to the field. The e.m.f. induced across the radius of disc is                [MH CET (Med) 2001]
  A)
             \[\frac{\pi }{10}\ V\]          done clear
  B)
             \[\frac{2\pi }{10}\ V\] done clear
  C)
             \[\pi \times {{10}^{-2}}V\]      done clear
  D)
             \[2\pi \times {{10}^{-2}}V\] done clear
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• question_answer9)
  A metal conductor of length 1m rotates vertically about one of its ends at angular velocity 5 radians per second. If the horizontal component of earth's magnetic field is \[0.2\times {{10}^{-4}}T\], then the e.m.f. developed between the two ends of the conductor is    [MP PMT 1992; AIEEE 2004]
  A)
             \[5\ mV\]                               done clear
  B)
             \[5\times {{10}^{-4}}V\] done clear
  C)
             \[50\ mV\]                             done clear
  D)
             \[50\ \mu V\] done clear
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• question_answer10)
  A conducting square loop of side L and resistance R moves in its plane with a uniform velocity v perpendicular to one of its sides. A magnetic induction B constant in time and space, pointing perpendicular and into the plane of the loop exists everywhere. The current induced in the loop is  [IIT 1989; MP PET 1997; MP PMT 1996, 99; MP PMT 2002]
  A)
             \[\frac{Blv}{R}\]clockwise       done clear
  B)
             \[\frac{Blv}{R}\]anticlockwise done clear
  C)
             \[\frac{2Blv}{R}\]anticlockwise                                         done clear
  D)
             Zero done clear
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• question_answer11)
  A player with 3 m long iron rod runs towards east with a speed of 30 km/hr. Horizontal component of earth's magnetic field is\[4\times {{10}^{-5}}Wb/{{m}^{2}}\]. If he is running with rod in horizontal and vertical positions, then the potential difference induced between the two ends of the rod in two cases will be                                         [MP PET 1993]
  A)
             Zero in vertical position and \[1\times {{10}^{-3}}V\]in horizontal position done clear
  B)
             \[1\times {{10}^{-3}}V\]in vertical position and zero is horizontal position done clear
  C)
             Zero in both cases done clear
  D)
             \[1\times {{10}^{-3}}V\]in both cases done clear
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• question_answer12)
  A coil of area 80 square cm and 50 turns is rotating with 2000 revolutions per minute about an axis perpendicular to a magnetic field of 0.05 Tesla. The maximum value of the e.m.f. developed in it is                                                [MP PMT 1994]
  A)
             \[200\pi \,volt\]                   done clear
  B)
             \[\frac{10\pi }{3}volt\] done clear
  C)
             \[\frac{4\pi }{3}\,volt\]     done clear
  D)
             \[\frac{2}{3}\]volt done clear
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• question_answer13)
  A conducting rod of length l is falling with a velocity v perpendicular to a uniform horizontal magnetic field B. The potential difference between its two ends will be [MP PMT 1994]
  A)
             2Blv                                           done clear
  B)
             Blv done clear
  C)
             \[\frac{1}{2}Blv\]                 done clear
  D)
             \[{{B}^{2}}{{l}^{2}}{{v}^{2}}\] done clear
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• question_answer14)
  A conducting wire is moving towards right in a magnetic field B. The direction of induced current in the wire is shown in the figure. The direction of magnetic field will be [MP PET 1995]
  A)
             In the plane of paper pointing towards right done clear
  B)
             In the plane of paper pointing towards left done clear
  C)
             Perpendicular to the plane of paper and down‑wards done clear
  D)
             Perpendicular to the plane of paper and upwards done clear
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• question_answer15)
  The current carrying wire and the rod AB are in the same plane. The rod moves parallel to the wire with a velocity v. Which one of the following statements is true about induced emf in the rod
  A)
             End A will be at lower potential with respect to B done clear
  B)
             A and B will be at the same potential done clear
  C)
             There will be no induced e.m.f. in the rod done clear
  D)
             Potential at A will be higher than that at B done clear
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• question_answer16)
  A long horizontal metallic rod with length along the east-west direction is falling under gravity. The potential difference between its two ends will          [MP PMT 1997]
  A)
             Be zero                                    done clear
  B)
             Be constant done clear
  C)
             Increase with time             done clear
  D)
             Decrease with time done clear
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• question_answer17)
  A two metre wire is moving with a velocity of 1 m/sec perpendicular to a magnetic field of 0.5 weber/m2. The e.m.f. induced in it will be                         [MP PMT/PET 1998; Pb PET 2003]
  A)
             0.5 volt                                    done clear
  B)
             0.1 volt done clear
  C)
             1 volt                                        done clear
  D)
             2 volt done clear
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• question_answer18)
  A metal rod moves at a constant velocity in a direction perpendicular to its length. A constant uniform magnetic field exists in space in a direction perpendicular to the rod as well as its velocity. Select the correct statement(s) from the following                                                                          [IIT JEE 1998]
  A)
             The entire rod is at the same electric potential done clear
  B)
             There is an electric field in the rod done clear
  C)
             The electric potential is highest at the centre of the rod and decreases towards its ends done clear
  D)
             The electric potential is lowest at the centre of the rod and increases towards its ends done clear
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• question_answer19)
  A conducting wire is dropped along east-west direction, then [RPMT 1997]
  A)
             No emf is induced done clear
  B)
             No induced current flows done clear
  C)
             Induced current flows from west to east done clear
  D)
             Induced current flows from east to west done clear
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• question_answer20)
  The magnetic induction in the region between the pole faces of an electromagnet is 0.7 weber/m2. The induced e.m.f. in a straight conductor 10 cm long, perpendicular to B and moving perpendicular both to magnetic induction and its own length with a velocity    2 m/sec is      [AMU (Med.) 1999]
  A)
             0.08 V                                       done clear
  B)
             0.14 V done clear
  C)
             0.35 V                                       done clear
  D)
             0.07 V done clear
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• question_answer21)
  A straight conductor of length 0.4 m is moved with a speed of 7 m/s perpendicular to the magnetic field of intensity of 0.9 Wb/m2. The induced e.m.f. across the conductor will be [MH CET (Med.) 1999]
  A)
             7.25 V                                       done clear
  B)
             3.75 V done clear
  C)
             1.25 V                                       done clear
  D)
             2.52 V done clear
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• question_answer22)
  A coil of N turns and mean cross-sectional area A is rotating with uniform angular velocity w about an axis at right angle to uniform magnetic field B. The induced e.m.f. E in the coil will be                                           [MP PMT 2002]
  A)
             NBA sinwt                              done clear
  B)
             NB w sinwt done clear
  C)
             NB/A sinwt                            done clear
  D)
             NBA w sinwt done clear
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• question_answer23)
  A conducting square loop of side l and resistance R moves in its plane with a uniform velocity v perpendicular to one of its sides. A magnetic induction B constant in time and space, pointing perpendicular and into the plane at the loop exists everywhere with half the loop outside the field, as shown in figure. The induced e.m.f. is                                [AIEEE 2002]
  A)
             Zero done clear
  B)
             RvB done clear
  C)
             VBl/R                                        done clear
  D)
             VBl done clear
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• question_answer24)
  A wheel with ten metallic spokes each 0.50 m long is rotated with a speed of 120 rev/min in a plane normal to the earth?s magnetic field at the place. If the magnitude of the field is 0.4 Gauss, the induced e.m.f. between the axle and the rim of the wheel is equal to                                                                 [AMU (Med.) 2002]
  A)
             \[1.256\times {{10}^{-3}}\,V\]                                           done clear
  B)
             \[6.28\times {{10}^{-4}}\,V\] done clear
  C)
             \[1.256\times {{10}^{-4}}\,V\]                                           done clear
  D)
             \[6.28\times {{10}^{-5}}V\] done clear
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• question_answer25)
  A metal rod of length 2 m is rotating with an angular velocity of 100 rad/sec in a plane perpendicular to a uniform magnetic field of 0.3 T. The potential difference between the ends of the rod is                                                [MP PET 2003]
  A)
             30 V                                          done clear
  B)
             40 V done clear
  C)
             60 V                                          done clear
  D)
             600 V done clear
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• question_answer26)
  The wing span of an aeroplane is 20 metre. It is flying in a field, where the vertical component of magnetic field of earth is 5 ´ 10?5 tesla, with velocity 360 km/h. The potential difference produced between the blades will be [CPMT 2003]
  A)
             0.10 V                                       done clear
  B)
             0.15 V done clear
  C)
             0.20 V                                       done clear
  D)
             0.30 V done clear
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• question_answer27)
  A horizontal straight conductor kept in north-south direction falls under gravity, then                     [MP PMT 2003]
  A)
             A current will be induced from South to North done clear
  B)
             A current will be induced from North to South done clear
  C)
             No induce e.m.f. along the length of conductor done clear
  D)
             An induced e.m.f. is generated along the length of conductor done clear
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• question_answer28)
  A rectangular coil of 300 turns has an average area of average area of \[25\ cm\times 10\ cm.\] The coil rotates with a speed of 50 cps in a uniform magnetic field of strength \[4\times {{10}^{-2}}T\] about an axis perpendicular of the field. The peak value of the induced e.m.f. is (in volt)  [KCET 2004]
  A)
                \[3000\pi \]               done clear
  B)
                \[300\pi \] done clear
  C)
                \[30\pi \]                   done clear
  D)
                \[3\pi \] done clear
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• question_answer29)
  A rod of length 20 cm is rotating with angular speed of 100 rps in a magnetic field of strength 0.5 T about it?s one end. What is the potential difference between two ends of the rod [Orissa PMT 2004]
  A)
             2.28 V                                       done clear
  B)
             4.28 V done clear
  C)
             6.28 V                                       done clear
  D)
             2.5 V done clear
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• question_answer30)
  A circular metal plate of radius R is rotating with a uniform   angular velocity \[\omega \]with its plane perpendicular to a uniform magnetic field B. Then the emf developed between the centre and the rim of the plate is [UPSEAT 2004]
  A)
             \[\pi \omega B{{R}^{2}}\]       done clear
  B)
             \[\omega B{{R}^{2}}\]   done clear
  C)
             \[\pi \omega B{{R}^{2}}/2\]   done clear
  D)
             \[\omega B{{R}^{2}}/2\] done clear
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• question_answer31)
  A circular coil of mean radius of 7 cm and having 4000 turns is rotated at the rate of 1800 revolutions per minute in the earth's magnetic field (B = 0.5 gauss), the maximum e.m.f. induced in coil will be                                               [Pb. PMT 2003]
  A)
             1.158 V                                    done clear
  B)
             0.58 V done clear
  C)
             0.29 V                                       done clear
  D)
             5.8 V  done clear
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• question_answer32)
  One conducting U tube can slide inside another as shown in figure, maintaining electrical contacts between the tubes. The magnetic field B is perpendicular to the plane of the figure. If each tube moves towards the other at a constant sped v then the emf induced in the circuit in terms of B, l and v where l is the width of each tube, will be   [AIEEE 2005]
  A)
              Zero                                           done clear
  B)
              \[2\,Blv\] done clear
  C)
              \[Blv\]                                       done clear
  D)
              \[-Blv\] done clear
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• question_answer33)
  The magnitude of the earth?s magnetic field at a place is \[{{B}_{0}}\] and the angle of dip is \[\delta \]. A horizontal conductor of length l lying along the magnetic north-south moves eastwards with a velocity v. The emf induced across the conductor is [Kerala PET 2005]
  A)
             Zero                                          done clear
  B)
             \[{{B}_{0}}l\,v\sin \delta \] done clear
  C)
             \[{{B}_{0}}l\,v\]                   done clear
  D)
             \[{{B}_{0}}l\,v\cos \delta \] done clear
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