Electromagnetic Induction Questions and Answers

negligible resistance and it is connected to a spring of spring constant 0 5 Nm see figure The assembly is kept in a uniform magnetic field of 0 1 T If the strip is pulled from its 573 HT CET Triumph Physics MCQs equilibrium position and released the number of oscillations it performs before its amplitude decreases by a factor of e is N If the mass of the strip is 50 grams its resistance 102 and air drag negligible N will be close to JEE Main 2019 A 1000 B 50000 X X X XXXXXXX XX

A rod of length 1m rotates about one of its end points with an angular velocity 2 rad sec in a plane perpendicular to the magnetic field B 2T as shown in the figure Then find magnitude of electric field in Sl unit at the mid point of the rod X 1m X X X X X B 2T

Consider a monochromatic beam of 2 points wavelength 6000 incident normally on a scanning Fabry Perot interferometer with n2 1 and F 400 The distance between the two mirrors is written as h h0 x Given h0 10 cm calculate the FWHM Dh for which the transmittivity will be one half O 9 5 O 8 5 O 7 5 O 10 5

A 800 turn coil of effective area 0 05 m is kept perpendicular to a magnetic field 5 105 T When the plane of the coil is rotated by 90 around any of its coplanar axis in 0 1 s the e m f induced in the coil will be

Electromag 5 A magnet is pushed N pole first into a coil as in the diagram below Which one of the following statements A to E is not true A Ap d is induced in the coil and causes a current through the galvanometer B The induced p d increases if the magnet is pushed in faster and or the coil has more turns C Mechanical energy is changed to electrical energy D The coil tends to move to the right because the induced current makes face X a N pole which is repelled by the N pole of the magnet E The effect produced is called electrostatic induction magnet N coil

A conducting rod ab of mass m can slide over two long frictionless conducting rails separated by distance The arrangement is kept in a uniform inward magnetic field B At time t 0 the rod is given velocity vo towards right The distance covered by the rod till its velocity becomes is given by kmv R B 2 Find the value of k a Vo

In a coil of resistance 100 2 a current is induced by changing the magnetic flux through it as shown in the figure The magnitude of change in flux through the coil is JEE Main 2017 10 Current amp A 250 Wb C 200 Wh Time 0 5 s B D 275 Wb 225 Wh

A long thin solenoid has 50 turns per cm and radius 1 10 cm The current in the solenoid is increasing at a uniform rate di dt The induced electric field at a point near the center of the solenoid and 3 50 cm from its axis is 8 00 10 V m Calculate di dt O6 63 A 9 20 A 09 34 A 0737 A

The conductor ABCD has the shape shown It lies in the yz plane with A and e on the y axis When it moves with a velocity v in a magnetic field B and emfe is induced between A and E ONO X Z A D e 0 if v is in the y direction and B is in the x direction e 2Bav if v is in the z direction and B is in the x direction e BAv if v is in the z direction and B is in the x direction

For an L shaped conducting rod placed in an uniform magnetic field B rotating with constant angular velocity w about an axis passing through one of its ends A and normal to the plane of the conductor induced emf X X X X X X dy w A X X X B X X X X X X X

Statement 1 The work done by field along a closed path is zero Statement 2 The induced electric field is non conservative ONO Statement 1 is True Statement 2 is True Statement 2 is a correct explanation for Statement 1 Statement 1 is True Statement 2 is True Statement 2 is NOT a correct explanation for Statement 1 Statement 1 is True Statement 2 is False Statement 1 is False Statement 2 is ture

At a certain instant coil A is in a 10 T external magnetic field and coil B is in a 1 T external magnetic field Both coils have the same area and are oriented at right angles to the field Which coil will have a greater emf induced in it It is impossible to know without more information about the fields Both Coils produce same emf O Coil B Coil A

The number of turns in the primary coil of a transformer is 1000 A A power of 2 kW is fed to it by a current of 0 1 A The number of turns in the secondary coil in order to produce a voltage of 200 V in it will be A 10 B 20 C 30 D 40

66 Electromagnetic Induction 22 In the last problem i e Q 21 the wire is shaped like a parabola y 4ax at the instant the rod cr the point a 0 Induced emf in the rod is 1 Bav a 0 2 2Bav

A coil of n turns and resistance R connected in series with a resistance R 2 combination is moved for time t second through flux to 02 The induced current in the circuit is A C n 0 0 Rt 2n 0 0 Rt LOS Log is 2 The 2n 0 0 3Rt 2n 3Rt

An inductor is connected to a direct voltage source through a switch Now A Very large emf is induced in inductor when switch is closed B C D Larger emf is induced when switch is opened Large emf is induced whether switch is closed or opened No emf is induced whether switch is closed or opened

Two inductors having self inductance L and L are arranged as shown in the given figure If M be the mutual inductance for the given pair of coils then find the between equivalent inductance A and B assume that the sense of coiling is same for both L A 0000000 1 L L M 3 L L 2M B 4 L oooo 2 L L 2M L L M

shape such that the 90 vertex is very close to an infinitely long conducting wire see the figure The wire is electrically insulated from the loop The hypotenuse of the triangle is parallel t the wire The current in the triangular loop is in the counter clockwise direction and increases at a constant rate of 10A s Which of the following statements s is are true 10 cm 90 Q C The magnitude of induced emf in the wire is volt kept A There is a repulsive force between the wire and the loop B If the loop is rotated at a constant angular speed about the wire an additional emf of fo volt is inducted in the wire D The induced current in the wire is in opposite direction to the current along the hypotenuse

Figure show a square loop of side 0 5 m and resistance 10 2 The magnetic field has a magnitude B 1 0 T The work done in pulling the loop out of the field slowly and uniformly in 2 sis A C X X X X X X X X X 3 125 10 J 1 2 104 J X X X V B D 6 25 10 J 5 0 10 J

9 An infinitely long wire carries current i along z axis Find flux through the right angled isosceles triangular region coplanar with the wire as shown in figure io K a a

A conducting rod of length 27 is rotating with constant angular speed o about its perpendicular bisector A uniform magnetic field B exists parallel to the axis of rotation The e m f induced between two ends of the rod is A Bol B Bo 2 1 Bol 8 C D zero B

In a coil rate of change of area is second and current becomes 5 m milli 1 ampere from 2 ampere in 2 x 10 s If of field is 1 tesla magnitude then self inductance of the coil is A C 2 H 20 H B 5 H LOT 10 H

A small loop of area of cross section 104 m is lying concentrically and coplanar inside a bigger loop of radius 0 628 m A current of 10 A is passed in the bigger loop The smaller loop is rotated about its diameter with an angular velocity w The magnetic flux linked with the smaller loop will be A 107 sin cot C 10 sin oot 107 cos ot cos ot B LB 10

A metal wire of area of cross section 1 8 X 107 m and specific resistance 9 x 10 2 m is bent into a square loop and moved with a constant speed in a uniform magnetic field of induction 2 Wb m What should be the speed of loop so that a current of 3 mA passes through it A 7 5 m s 75 x 10 m s B D 0 5 x 10 m s 1 9 102 m s

A conducting rod AB makes contact with the metal rails AD and BC which are 0 50 m apart If a uniform magnetic field of induction of 0 50 weber m acts perpendicular to plane of figure pointing downward then calculate the rate at which mechanical work is done by external force v 4 m s constant R 0 2 ohm x A V X X X X X X X X X X X A 4 W C 6 W X X X X X X X X X X X X x B x X x B x X X X X X X X X xxx X X X X X LOBY X XD X X X X X C 5 W D 7 W

A magnet is brought towards a coil i speedly ii slowly then the induced e m f induced charge will be respectively More in first case More in first case More in first case Equal in both case Less in first case More in second case Less in first case Equal in both case A B C D

A coil of radius 1 cm and 100 turns is placed in a magnetic field of 10 gauss such that its plane makes an angle 30 with the field The magnetic flux through the coil in S I unit is A 0 5 Wb C B 0 5 Wb D 5 x 10 Wb 0 5 x 104 Wb

In a coil of area 10 cm and 10 turns the magnetic field is directed perpendicular to the gauss s plane and is changing at the rate of 108 The resistance of the coil is 20 2 The current in the coil is A 5 ampere B 0 5 ampere C 0 05 ampere 5 108 ampere D

A square loop of side 22 cm is converted into circular loop in 0 4 s A uniform magnetic field of 0 2 T directed normal to the loop then the e m f induced in the loop is A 6 6 x 10 V 3 C 6 6 x 104 V B D 6 6 10 5 V 6 6 10 8 V X

A given wire is bent into a circular loop of radius 7 cm and is placed perpendicular to a magnetic field of 1 0 T Within 0 1 second the loop is changed to a 100 cm square and the field increases to 1 8 T The e m f induced in the coil will be A 13 mV C 39 mV LB D 26 mV 52 mV

A rectangular coil of 100 turns and dimensions of 10 cm x 5 cm is placed perpendicular to a uniform magnetic field of induction 0 1 T If the magnetic induction drops to 0 05 T in 0 05 s then the e m f induced in the coil is 0 05 V 5 V A 0 005 V C 0 5 V B D

Match R L C circuit in List I with impedance in List II R List I R ww R CL m RW W m L m ooooo L C HH List II w is angular frequency of source N OL OC OL R C 1 0 LC 1 0 R C 3 Z R R OL C 1 06 1

Q 16 Your Answer 2m 81 85 86 Option 1 Option 2 3m A square loop is carrying a steady current I and the magnitude of its magnetic dipole moments is m If this square loop is changed to a circular loop and it carries the same current the magnitude of the magnetic dipole moment of the circular loop will be Option 3 2m Option 4 4m T Correct Answer 4m T

35 The network shown in the figure is a part of a complete circuit If at a certain instant the current i is 5 A and is decreasing at the rate of 10 A s then www V V is NCERT XII 1 223 B A 1 5 V 2 10 V 3 15 V ww VA 5X1 15

With the decrease of current in the primary coil from 2 ampere to zero value in 0 01 second the e m f generated in the secondary coil is 1000 volt The mutual inductance of the two coil is A 1 25 henry B 2 50 henry 5 00 henryonib D 10 00 henry

A rectangular loop of area 0 2 m is lying in a magnetic field of 5 x 102 tesla at an angle of 60 with the magnetic field The magnetic flux passing through this loop will be A 5 x 10 weber 3 B 5 x 103 weber C 5 x 102 weber

An average induced e m f of IV appears in a coil when the current in it is changed from 10 A in one direction to 10 A in opposite direction in 0 5 s Self inductance of the coil is A 25 mH C 75 mH B D 50 mH 100 mH

4 A solid cylinder of mass m length 1 and radius R is placed on two horizontal paralle rails of separation 1 The cylinder carries a constant current i A uniform magnetic fiel B directed vertically upwards is switched on After travelling a distance a its speed assume rolling without slipping 2ila B 4ila B A B 3m 3m 2ila B m D 4ila B m

In an L C oscillation capacitor can be Qo If at any instant electrical 3 4 energy is th of the magnetic energy then the charge on capacitor at that instant is NCERT Pg 256 2 Qo 3 O 10 10dS 1 3 2 INIC Qo Qo

The voltage shown in the figure is applied to a 2 5 F capacitor and a 0 5 H inductor separately choose correct graph mA A C 0 123 E ic current across capacitor Energy stored in inductor V volt 20 Of A 4 5 t ms 10 0 10 20 1 2 3 4 5 1 2 3 4 5 t ms t ms B mA D current across inductor E Energy stored in capacitor O 15 t ms 1 2 3 4 5 t ms

A small square loop of wire of side I is placed inside a large square loop of side L L 1 If the loops are coplanar and their centres coincide the mutual inductance of the system is directly proportional to 1 L 1 2 I L 3 L 1 4 P L

over a triangular wire CDE with a constant velocity V in a uniform magnetic field B directed into the plane of the paper Resistance per unit length of each wire is p Then F A A G E H 1 Induced emf in the loop remains constant 2 Induced emf increases with time 3 Induced emf decreases linearly with time 4 May increase or decrease

A conducting loop in the shape of a right angled isosceles triangle of height 10 cm is kept such that the 90 vertex is very close to an infinitely long conducting wire see the figure The wire is electrically insulated from the loop The hypotenuse of the triangle is parallel to the wire The current in the triangular loop is in counterclockwise direction and increased at a constant rate of 10As Which of the following statement s is are true 2016 Adv 10 cm 90 a There is a repulsive force between the wire and the loop b If the loop is rotated at a constant angular speed about the wire an additional emf of Movolt is induced in the wire T c The magnitude of induced emf in the wire is volt to d The induced current in the wire is in opposite direction to

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 emf induced across the radius of disc is T 10 V V TX10 V

A conductor of mass m and length is given velocity Vo on a smooth horizontal conducting rails as shown Resistance is negligible for all Choose the correct options x is displacement of conductor B reeeeeeee Current through the inductor is Current through the inductor is BI L 2 BI X L Maximum displacement of conductor will be BI m L

Magnetic field in the cylindrical region is varying with time t as B Bot If a metal rod AB of length I is placed as shown then R B Electric field component along the rod at point A is BO R 12 Electric field component along the rod at point A is BOR 1 4 Bo 2 Induced emf across the ends of rod is Bol 2

A square loop of side a 10 cm with its sides parallel to the x and y axes is moved with a constant velocity v 8 cm sec in the positive x direction in an environment in which there aB is a magnetic field along the z direction It has a gradient ax 10 tesla m along x axis dB and the time decreasing rate dt The current in the loop is found to be x x 10 A Find the value of x 10 tesla sec The resistance of he square loop is 502

Applied 6 There is no resistance in the inductive circut Kirchhoff s voltage law for the circuit is V V sino t 1 V L 0 di dt 3 V L di 0 dt 000000 2 V L dt 4 None of these

In a series RLC circuit potential differences across R L and C are 30 V 60 V and 100 V respectively as shown in figure The e m f of source in volts 30 V 60 V 100 V voovo 1 190 3 50 R L C 2 70 4 40 ltage acro

Shown in the figure is a circular loop of radius rand resistance 3 A variable magnetic field of induction B Boe is established inside the coil If the switch S is closed at t 0 and H H is power loss just after closing the switch in the coil and resistance respectively then 2R 3 H H H B B2 4 6R B r4 24R B 2r4 8R B 4 4R L S