Page 1 :
The Achiever Classes of Physics, XII-MCQ TEST- EMI, , MULTIPLE CHOICE QUESTIONS, , Choose and write the correct option in the following questions., , Whenever the flux linked with a circuit changes, there is an induced emf in the circuit. This, emf in the cirenit lasts, , (a) for a very short duration, , (6) for a long duration, , (cy forever, , (@) as long as the magnetic flux in the circuit changes., , 2. The area of a square shaped coil is 10°? m?. Its plane is perpendicular to a magnetic field of, , 4., , strength 10~ "I, The magnetic flux linked with the coil is, fa) 10 Wb () 10° Wb (©) 10° Wb (d) 100 Wb, , An arca A = 0.5 m* shown in the figure is situated in a uniform magnetic field 8 = 4.0 Wb/m*, and its normal makes an angle of 60° with the field. ‘he magnetic Mux passing through the, , areaA would be equal to ;, —+—____A—_, (a) 2.0 weber (6) 1.0 weber (e) 3 weber (d) 0.5 weber, , A square of side L. meters lies in the X-¥ plane in a region, where the magnetic field is given, by B= B,(2i + 3) + 48)T, where 2, is constant. The magnitude of flux passing through the, , square is [NCERT Exemplar], (a) 2B, 17 Wb (6) 9 Rg 1? Wh, () 48,12 Wb (d) ¥291,P Wh, , A loop, made of straight edges has six corners at A(0, 0, 0), B(L, O, 0), CL, L, 0), D(O, L, 0), E(0, L, L) and F(0, 0, L). A magnetic field B= #, (i +h)T is present in the region. The flux, , passing ¢ through the loop ABCDEFA (in that order) is [NCERT Exemplar], (a) BL? Wh (b) 2B, 1? Wh, {e) ¥28,2 Wb (d) 4B, 12 Wb, An emf is produced in a coil, which is not conneeted to an external voltage source, This can, be duc to |NCERT Exemplar}, , {a) the coil being ina time varying magnetic fell., (6) the coil moving ina time varying magnetic field., () the coil moving in a constant magnetic field., , (d) all of the above., , Er. Sparsh Verma ( M.Sc, GATE, B.Tech (EEE)), Email: sparsh.kk@gmail.com mob: 7417852731, , Page | of 4

Page 2 :
7, , 18., , The Achiever Classes of Physics, , , , XII-MCQ TEST- EMI, A cylindrical bar magnet is rotated about its axis (Figure given alongside). ans A, A wire is connected from the axis and is made to touch the cylindrical <a:, surfuce through a contact. Then [NCERT Exemplar], fa) a direct current flows in the ammeter A,, bar —+| —+, (6) no current flows through the ammeter A, magnet | @, {) an alternating sinusoidal current flows through the ammeter A with a, time period 7'=2n/a. Lo, , , , (d) A time varying non-sinusoidal current flows through the ammeter A., , A copper ring is held horizontally and a magnet is dropped through the ring with its length, along the axis of the ring. The acceleration of the falling magnet is, , (2) equal to that due to gravity, , (6) less than that due to gravity, , © more than that due to gravity, , (d) depends on the diameter of the ring and the length of the magnet, , There are two coils A and B as shown in the figure. A current starts flowing in B as shown,, when A is moved towards B and stops when A stops moving. The current in A is counter, clockwise, 2 is kept stationary when A moves, We can infer U (NCERT Exemplar], , A B, C» C), {a) there is a constant current in the clockwise direction in A., (6) there is a varying current in A., fe) there is no current in AL, @) there is a constant current in the counterclockwise divection in A., Same as the above problem except the coil A is made to rotate about a vertical axis refer to the, , figure. No current flows in Bif A is at rest. The current in coil A, when the current in B (at ¢ = 0), is counterclockwise and the coil A is as shown at this instant, (= 0,is = [NCERT Exemplar), , OO, , , , (a) constant current clockwise. (0) varying current clockwise., , (e) varying current counterclockwise. (d@} constant current counterclockwise., , Lenz's law is essential for, , (a) conservation of energy {8) conservation of mass, , © conservation of momentum (d) conservation of charge, , The self inductance 7. ofa solenoid of length / and area of crosssection A, with a fixed number, of turns N increases as [NCERT Exemplar], (a) Land A increase, (6) { decreases and A increases., , (ce) Cincreases and A decreases. (d) both and A decrease., , A thin-circular ring of area A is held perpendicular to a uniform magnetic field of induction B., A small cut is made in the ring and a galvanometer is connected across its ends in such » way, that the total resistance of the circuit is 2. When the ring is suddenly squeezed to zero area,, the charge Mowing through the galvanometer is, , BR AB, @) ) () ABR (a) a, , Er. Sparsh Verma ( M.Sc, GATE, B.Tech (EEE)), Email: sparsh.kk@gmail.com mob: 7417852731, , Page 2 of 4

Page 3 :
14,, , 15., , 17., , 21., , The Achiever Classes of Physics, XII-MCQ TEST- EMI, , , , , , , , , , A conducting square loop of side I. and resistance R moves in its : . <2 . . ; :, plane with a uniform velocity v perpendicular to one of its sides. . |, y oa tie sige, A magnetic induction B constant in time and space, pointing » y |, y yo x x, perpendicular and into the plane of the loop exists everywhere as, a ce ee, in given figure. The current induced in the loop is xxKRMRKRNH KR, (a) BhyR clockwise {h) BLYR anticlockwise, , (©) 2BhyYR anticlockwise (d) zero., , Inductance plays the role of, , (2) inertia (®) friction, , {c) source of emf (d) force, , A circular coil expands radially in a region of magnetic field and no electromotive force is, , produced in the coil. This can be because INCERT Exemplar|, , (a) the magnetic field is constant., , (6) the magnetic field is in the same plane as the cirenlar coil and it may or may not vary., , (e) the magnetic field has a perpendicular (to the plane of the coil) component whose magnitude, is decreasing suitably,, , (d) bouh (6) and (¢), , , , When the curresi coil changes from 8 A to 2 A in SX 107 second, the enuf induced in the, coil is 2 volt, The self-inductance of the coil, in millihenry, is, , fa) 1 @)5, , 20 @ 10, , The mutual inductance of two coils depends upon, , (a) medium between coils (6) scparation between coils, , fe) both on (a) and (4) (@) none of (a) and (hb), , Due to relative motion of a magnet with respect toa coil, an emf is induced in the coil. Identify, the principle involved., , (e) Gauss’s law (6) Biot-Savart law, , (ce) Ampere’s circuital law (@) Faraday's law, , In Furaday’s experiment of electromagnetic induction, more deflection will be shown by, galvanometer, when, , (@) magnet is in uniform motion towards the coil, , (6) maguet is in accelerated motion towards the coil, , (e) amaguet is in uniform motion away from the coil, , (@) magnet is at vest near the coil, , If both the number of turns and core length of an inductor is doubled keeping other factors, constant, then its self-inductance will be, , (@) halved (6) quadrupled, , © unaffected (d) doubled, , Oscillating metallic pendulum in a uniform magnetic field directed perpendicular to the, plane of oscillation, , (@) vemains unaffected (6) oscillates with changing frequency, , (© slows down (d) becomes faster, , A metallic cylinder is held vertically and then a small magnet is dropped along its axis. It will, fall with, , (@) acceleration a = g (6) constant velocity a = 0, , (e) acceleration a > g (d) acceleration a < g, , Er. Sparsh Verma ( M.Sc, GATE, B.Tech (EEE)), Email: sparsh.kk@gmail.com mob: 7417852731, , Page 3 of 4

Page 4 :
Page 4 of 4, , A, The Achiever cites of Physics, XII-MCQ TEST- EMI, , , , ye A conducting square loop of side / and resistance R moves in its plane, , 24. An emf of 200 V is induced in a circuit when current in the circuit falls from 5 A to 0 A, in 0.1 second. The self-inductance of the circuit is, , (a) 35H ~\ (6) 39H fo 4H (dd) 42H, 25. A small metal wire is dragged across the gap between the poles of a magnet in, , 0.45, magnetic Mux in the wire is 8 x 10 Wb, then emf induced in the wire is, , (a) 85 19 v (6) Gx 10° V (4x 108 Vv (@)2x 10°V e!, 26. ¢ humber of turns per unit length of the coil of a solenoid is doubled keeping other ¢ - same, then its self-inductance will be YD, ~ NO four times (6) eight times (©) halved (d) doubled \, , with a uniform velocity » 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 emf is e, (@) zero (6) RoB (c) wBUR (d) wBi <\, 28. A wheel with ten metallic spokes each 0.50 m long is rotated with a revimin in a, plane normal to the earth's magnetic field at the place. If the magnitudé@ of the field is 0.4 G, the induced emf between the axle and the rim of the wheel is equal,, (a) 1.256 x 10° V (6) 6.28 x 1o*V {e) 1.256 x 10“VC, 6.28 x 10°V, 29. Ina circuit with a coil of resistance 2 ohms, the magnetic flux chunges from 2.0 Wb (o 10.0 Wb, in 0.2 second. The charge that flows in the coil during this 8, (a) 5.0 coulomb (6) 0.8 coulomb fe) 1.0 (¢) 4.0 coulomb, 30. The direction of induced current is such that it very cause that has produced it., ‘This is the law of, @) Lenz (®) Faraday Retina (@) Fleming, 31. The magnetic flux through a circuit of resistance R changes by an amount Ad in time At,, then the total quantity of clectric charge Q, passing during this time through any point of the, circuit is given by, ab _ ab, @) 4Q==- (@) AQ=Z>xR, Ab Ab, {e) AQ=-7 +R @) AQ= =, 32. The dimension of magnetic flux is, (@) M't2ra7 (6) M*LST A! ( M12T?a7 (d) META!, 33. Lenz's law isa comsequence of the law of conservation of, (a) mass (6) charge (©) momentum (d) energy, 34. The phy quantity expressed in henry is é!, {a) ic flux (6) self-inductance Xe, tic permeability (d) magnetic induction ©, 9 current in a circuit drops from 10 A to 2 A in 2 seconds, the induced emf developed in A, “\. the circuit is 16 volts. The self inductance of the circuit is, a fa) 16 henry (6b) 8 henrv fe) 6 henry (d\) 4 henrv a\x, , &, , Er. Sparsh Verma ( M.Sc, GATE, B.Tech (EEE),, Email: sparsh.kk@gmail.com mob: 7417852731 aw