Electromagnetic Induction — practice questions

129 curated practice questions from Electromagnetic Induction (Physics Class 12, CBSE) — 23 medium, 101 easy, 5 hard. Every question includes the final answer free; step-by-step worked solutions with a free account.

• Figure shows a rectangular conductor PSRQ in which movable arm PQ has a resistance r and resistance of PSRQ is…
• The physical quantity which is measured in the unit of Wb A –1 is
• A wire of irregular shape turning into a circular shape in a magnetic field which is directed into the paper. The…
• The current in a coil of 15 mH increases uniformly from zero to 4 A in 0.004 s. The emf induced in the coil will be:
• The equivalent inductance of two inductors is 2.4 H when connected in parallel and 10 H when connected in series. What…
• The direction of induced current in the coils A and B in the situation shown in the figure is
• A wheel with 20 metallic spokes each of length 0.8 m long is rotated with a speed of 120 revolution per minute in a…
• The magnetic flux linked with a coil of N turns of area of cross section A held with its plane parallel to the field B…
• A metal ring kept (supported by a card I board) on the top of a fixed solenoid carry a current I as shown in figure…
• In the figure, galvanometer G gives maximum deflection when
• A circular coil of radius 8 cm, 400 turns and resistance 2 Ω is placed with its plane perpendicular to the horizontal…
• The mutual inductance M 12 of a coil 1 with respect to coil 2
• A copper rod of length l rotates about its end with angular velocity ω in a uniform magnetic field B . The emf…
• A conducting circular loop is placed in a uniform magnetic field, B = 0.025 T with its plane perpendicular to the loop…
• A small flat search coils of area 4 cm 2 with 20 closely wound turns is positioned normal to the field direction and…
• A metal rod of length 50 cm is held vertically and moved with a velocity of 10 ~m / s towards east. The horizontal…
• A rod PQ of resistance R lies across frictionless conducting rails in a constant uniform magnetic field B , as shown in…
• Two inductors of inductance L each are connected in series with opposite magnetic fluxes. The resultant inductance is…
• Two coils of self-inductance 2 mH and 8 mH are placed so close together that the effective flux in one coil is…
• The north pole of a bar magnet is moved towards a coil along the axis passing through the centre of the coil and…
• A magnetic flux through a stationary loop with a resistance R varies during the time interval τ as φ = at (τ – t )…
• Consider a solenoid of length l and area of cross-section A with fixed number of turns. The self-inductance of the…
• The self inductance of a long solenoid cannot be increased by
• In the given figure, the loop is fixed but the straight wire can move. The straight wire will:
• Two solenoids of equal number of turns have their lengths and the radii in the same ratio 1 : 2. The ratio of their…
• Faraday’s laws are consequence of the conservation of
• Two circular coils can be arranged in any of three situations as shown in the figure. Their mutual inductance will be…
• A metal conductor of length 1 m rotates vertically about one of its ends with an angular velocity 5 rad s –1 . If the…
• In the given figure current from A to B in the straight wire is decreasing. The direction of induced current in the…
• A coil of area 100 cm 2 is kept at an angle of 30 o with a magnetic field of 10 -1 T. The magnetic field is reduced to…
• A conducting square loop of side L and resistance R moves in its plane with a uniform velocity v perpendicular to one…
• The mutual inductance of two coils C _1 and C _2 is 20 mH . In coil C _1 , the current changes from 4 A to zero in 0.2…
• A magnetic field B is confined to a region r ≤ a and points out of the paper (the z -axis), r = 0 being the centre of…
• Two coils A and B are separated by a certain distance. If a current of 4 A flows through A , a magnetic flux of 10 –3…
• If the number of turns per unit length of a coil of solenoid is doubled, the self-inductance of the solenoid will
• By a change of current from 5 to 10 amperes in 0.1 second, the self induced emf is 10 V. The change in the energy of…
• The equivalent inductance between A and B is
• An infinitely long cylinder is kept parallel to a uniform magnetic field B directed along positive z axis. The…
• The coefficient of mutual inductance of two coils depends on
• A circular coil of radius 10 cm, 500 turns and resistance 2 is placed with its plane perpendicular to the horizontal…
• A metallic rod of 1 m length is rotated with a frequency of 50 revolution per second, with one end hinged at the centre…
• A solenoid of length 30 cm with 10 turns per centimetre and area of cross-section 40 cm 2 completely surrounds another…
• In the figure X is a coil wound over a hollow wooden pipe. A permanent magnet is pushed at a constant speed v from the…
• A jet plane is travelling west at the speed of 1600 km h –1 . The voltage difference developed between the ends of the…
• The emf induced in a coil rotating in a magnetic field does not depend upon the following:
• A square of side x metre lies in the x - y plane in a region, where the magnetic field is given by B =B_ 0 (3 i +4 j +5…
• A circular coil of radius 8.0 cm and 40 turns is rotated about its vertical diameter with an angular speed of 25 rad s…
• There is a uniform magnetic field directed perpendicular and into the plane of the paper. An irregular shaped…
• Switch S is closed at t = 0. After sufficiently long time, an iron rod is inserted into the inductor L . Then, the…
• The energy stored in an inductor of self inductance L henry carrying a current of I ampere is
• Assertion (A): The mutual inductance between two coils is maximum when the coils are wound on each other. Reason (R)…
• A coil of area of cross-section 0.5 ~m ^ 2 is placed in a magnetic field acting normally to its plane. The field varies…
• A square shaped coil of side 10 cm, having 100 turns is placed perpendicular to a magnetic field which is increasing at…
• Two coils have self-inductance L 1 = 4 mH and L 2 = 1 mH respectively. The currents in the two coils are increased at…
• Whenever the flux linked with a circuit changes, there is an induced emf in the circuit. This emf in the circuit lasts
• A small square loop of wire of side l is placed inside a large square loop of wire of side L (>> l ). The loops are…
• The self-inductance of a solenoid of 600 turns is 108 mH. The self-inductance of a coil having 500 turns with the same…
• Lenz's law is a consequence of the law of conservation of
• You are required to design an air-filled solenoid of inductance 0.016 H having a length 0.81 m and radius 0.02 m. The…
• A circular coil of diameter 15 mm having 300 turns is placed in a magnetic field of 30 mT such that the plane of the…
• If N is the number of turns in a coil, the value of self-inductance varies as
• Assertion (A): Lenz's law is a consequence of the law of conservation of energy. Reason (R): There is no power loss in…
• A coil has 100 turns, each of area 0.05 m ^ 2 and total resistance 1.5 . It is inserted at an instant in a magnetic…
• A coil of area 0.4 m 2 has 100 turns. A magnetic field of 0.04 Wb m –2 is acting normal to the coil surface. If this…
• The self inductance L of a solenoid of length l and area of crosssection A, with a fixed number of turns N increases as
• Assertion (A): It is difficult to move a magnet into a coil of large number of turns when the circuit of the coil is…
• A conducting loop is placed in a magnetic field, normal to its plane. The magnitude of the magnetic field varies with…
• A rectangular loop of area vector A =[ i + 3 j ] 10^ -2 ~m ^ 2 is placed in a magnetic field B = [4 .0 t ^ 2 +2 .0 ] i…
• The mutual inductance of two coils, in a given orientation is 50 mH. If the current in one of the coils changes as i…
• If the self inductance of 500 turns coil is 125 mH, then the self inductance of the similar coil of 800 turns is
• A square loop of side 12 cm and resistance 0.60 Ω is placed vertically in the east-west plane. A uniform magnetic field…
• The direction of induced current in the right loop in the situation shown by the given figure is
• In a coil current falls from 5 A to 0 A in 0.2 s. If an average emf of 150 V is induced, then the self inductance of…
• A rectangular coil of area A is kept in a uniform magnetic field B such that the plane of the coil makes an angle with…
• A loop, made of straight edges has six corners at A (0 , 0 , 0), B ( L , 0, 0), C ( L, L, 0), D (0, L , 0), E (0 , L, L…
• Two coils are placed near each other. When the current in one coil is changed at the rate of 5 ~A / s , an emf of 2 mV…
• A conducting ring of radius r is placed in a varying magnetic field perpendicular to the plane of the ring. If the rate…
• A metallic square loop ABCD is moving in its own plane with velocity v in a uniform magnetic field perpendicular to its…
• Whenever a magnet is moved either towards or away from a conducting coil, an emf is induced, the magnitude of which is…
• A rectangular loop of sides 6 cm and 2 cm with a small cut is moving out of a region of uniform magnetic field of…
• A coil of inductance 300 mH and resistance 2 W is connected to a source of voltage 2 V. The current reaches half of its…
• The self inductance of a coil having 400 turns is 10 mH. The magnetic flux through the cross section of the coil…
• The variation of induced emf (ε) with time ( t ) in a coil if a short bar magnet is moved along its axis with a…
• A long solenoid S has n turns per metre, with diameter a . At the centre of this coil, we place a smaller coil of N…
• A 100 mH coil carries a current of 1 A. Energy stored in its magnetic field is
• A circular coil expands radially in a region of magnetic field and no electromotive force is produced in the coil. This…
• Two long solenoids of radii r_ 1 and r_ 2 ( r_ 1 ) and number of turns per unit length n _ 1 and n _ 2 respectively are…
• A cylindrical bar magnet is rotated about its axis as shown in figure. A wire is connected from the axis and is made to…
• Which of the following does not use the application of eddy current?
• The direction of induced current in the loop abc is:
• Assertion (A): Faraday's laws are a consequence of the conservation of energy. Reason (R): In a purely resistive a.c…
• A circular coil of radius 10 cm is placed in a magnetic field B =(1.0 i +0.5 j ) mT such that the outward unit vector…
• An electromagnet has stored 648 J of magnetic energy when a current of 9 A exists in its coils. What average emf is…
• The magnetic flux through a coil perpendicular to its plane and directed into paper is varying according to the…
• Two identical coaxial coils P and Q carrying equal amount of current in the same direction are brought nearer. The…
• If number of turns in primary and secondary coils is increased to two times each, the mutual inductance
• A long solenoid with 10 turns per cm has a small loop of area 3 cm 2 placed inside, normal to the axis of the solenoid…
• The radius of the circular conducting loop shown in figure is R. Magnetic field is decreasing at a constant rate a…
• A 2 m long solenoid with diameter 2 cm and 2000 turns has a secondary coil of 1000 turns wound closely near its…
• The north pole of a bar magnet is rapidly introduced into a solenoid at one end (say A ). Which of the following…
• A sliding rod AB of resistance R is shown in the figure. Here magnetic field B is constant and is out of the paper…
• If a coil of 40 turns and area 4 cm 2 is suddenly removed from a magnetic field, it is observed that a charge of 2 × 10…
• The magnetic flux linked with a closed coil (in Wb) varies with time t (in s) as =5 t ^ 2 +4 t -2 . If the resistance…
• Lenz’s law is a consequence of the law of conservation of
• A 10 V battery connected to 5 Ω resistance coil having inductance 10 H through a switch drives a constant current in…
• A conducting loop is placed in a uniform magnetic field with its plane perpendicular to the field. An emf is induced in…
• In an inductor of self-inductance L = 2 mH, current changes with time according to relation, I = t 2 e – t At what time…
• A circular copper disc 10 cm in diameter rotates at 1800 revolution per minute about an axis through its centre and at…
• Two coils, A and B are as shown in the figure. A current starts flowing in B as shown, when A is moved toward B and…
• A circular coil with a cross-sectional area of 4 cm 2 has 10 turns. It is placed at the centre of a long solenoid that…
• A 2 m long metallic rod rotates with an angular frequency of 200 rad s –1 about an axis normal to the rod passing…
• As shown in the figure, a metal rod makes contact with a partial circuit and completes the circuit. The circuit area is…
• An air cored solenoid with length 20 cm, area of cross section 20 cm 2 and number of turns 400 carries a current 2 A…
• A current of 1 A through a coil of inductance of 200 mH is increasing at a rate of 0.5 A s –1 . The energy stored in…
• Two conducting circular loops of radii R 1 and R 2 are placed in the same plane with their centres coinciding. If R 1 >…
• The figure shows a wire sliding on two parallel conducting rails placed at a separation l . A magnetic field B exists…
• The current in the primary coil of a pair of coils changes from 7 A to 3 A in 0.4 s. The mutual inductance between the…
• As a result of change in the magnetic flux linked to the closed loop shown in figure, an emf, V volt is induced in the…
• The total charge induced in a conducting loop when it is moved in magnetic field depend on
• A rod of length l rotates with a uniform angular velocity w about an axis passing through its middle point but normal…
• A short solenoid of radius a , number of turns per unit length n 1 , and length L is kept coaxially inside a very long…
• When the rate of change of current is unity, the induced emf is equal to
• A coil of N turns is placed in a magnetic field B such that B is perpendicular to the plane of the coil. B changes with…
• When current in a coil changes at a steady rate from 8 A to 6 A in 4 ms, an emf of 1.5 V is induced in it. The value of…
• The magnetic flux linked with a coil changes with time t as = (8 t ^ 2 +5 t +7 ) , where t is in seconds and is in Wb…
• The self inductance L of a solenoid of length l and area of cross-section A , with a fixed number of turns increases as
• A pair of adjacent coils has a mutual inductance of 2.5 H. If the current in one coil changes from 0 to 40 A in 0.8 s…
• Direction of current induced in a wire moving in a magnetic field is found using
• A conductor is moving with the velocity v in the magnetic field and induced current is I . If the velocity of conductor…

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