Electromagnetic Induction Questions and Answers

In the circuit show indicated a uniform magnetic field which is directed into the page and decreasing in magnitude at the rate of 150 T s The reading of ammeter is 1092 Size of the loop 10 x 10 cm Options O 0 15 A O 0 35 A O 0 50 A 00 650 B 5 V

If the circular conductor undergoes thermal expansion while it is in a uniform magnetic field a current will be induced in clockwise around it If B is the magnitude of the magnetic field then its direction is L Options O Bi Ri

48 One conducting U tube can slide into another U tube maintaining electrical contacts between them A magnetic field B is acting perpendicular to the plane of slide If each tube moves at a constant speed v towards each other then the emf induced in the circuit is c Blv d Blv a Blv b 0 2 2Blv 20 54

A coil of resistance 10 Q and inductance 10 H and a battery of emf V are connected in series through a switch k After the steady state the switch is opened The voltage falls to zero value in 2 millisecond and the induced emf is 2000 V Find the emf of the battery Options 01 V O 1 5 V 0 4 V O 2 5 V

Find the emf in a coil of of 50 tur ns each of area 50 cm 2 when ma king 1800 rev min in a uniform fiel d flux density 6x10 3 T Sir the answer is given as 7 2 10 2 V But I am getting the answer as 0 4 5 V Please help

5 A horizontal metal wire is carrying electric current from the north to south Using a uniform magnetic field it is to be prevented from falling under gravity The direction of the magnetic field should be towards the O west O north O south O east 1 F

29 The radius of the circular conducting loop shown in figure is R Magnetic field is decreasing at a constant rate at Resistance per unit length of the loop is p Then current in wire AB is AB is one of the diameters Ra a from B to A 6 aza g 20 from A to B 2Rce c d zero from A to B X A B

A circular frame of radius r made by a insulating material An equilateral triangle constructed with in it If it carries I current then magnetic field produced at geometrical centre is

Draw the circuit diagram of an inverting amplifier of gain 10 and input impedance 10 kn The circuit should work for de as well as ac signals You are allowed to use only one op amp and two resistors If the circuit should amplify signals in the range 1 6 V to 1 6 V what should be the op amp supply voltages

rails as shown in the figure mathange mathonan mathon mathonne mothers X Rahmathon mat mat go X mathango X X mathongo Y mathongo mathon mathongo mathanga mathongo mathongo B mothongo Rongo mathongo mathonga I and I are in clockwise direction mathango mothenge mathongo Two resistors R and R are connected across the ends of the rails There is a uniform magneticongo mathango mathongo mathongo field B pointing into the page An external agent pulls the bar to the left at a constant speed uhongo mathongo mathongo The correct statement about the directions of induced currents I and 1 hongo flowing through R and R respectively is athango 1 Both I and I2 are in anticlockwise direction mathonge 2 Both I mathongo 3 I is in clockwise direction and I2 is in anticlockwise direction mathongo mathengsmathonge go mathongo mathongo mathongo mathongo

9 A 1 ph transformer has a trans ratio 1 2 and is connected to pure resis tive load If this magneting current is 1A and the secondary current is 1A If losses are neglected then primary current is a 1A 1 2 000 10 leaving 1658 b 2A

A bracket is placed on a horizontal smooth floor and is pulled by a constant force of F 6 N horizontally A block is placed on a bracket as shown The block is projected with velocity Vo relative to the bracket as shown Horizontal surface of the bracket is smooth whereas the vertical surface is rough Find the time after which the block stops relative to the bracket Consider m 1 kg 0 5 Vo 4 ms M 5 kg rough m smooth M

Equivalent inductance of the following circuit between terminals A and B is 2 H mmmmm 2 H H 4 H 3 H mmmmmm 2 H mmmmm B

The primary coil of a transformer has 100 turns and the secondary coil has 500 turns The primary is connected to an alternating voltage source with rms value 120 volts Assuming no flux leakage the maximum value of the rate of change of flux dd in dt T m s in the secondary circuit is closest to A 850 B 600 C 430 D 40 81

A rectangular coll made up of turns of wire sides a 2 45m and b 4 89m rests on the xy axis There is a magnetic field that crosses the coil entering the screen z which for a period of 16 3s changes it intensity linearly from 17 1T to 21 5T What will be the intensity of the induced voltage and the direction of the induced current in the coil in that period that the magnetic field increases in intensity linearly X X X X X X X X b X a X X X X X B t X 13 58V and the current flows counterclockwise O 22 64V and the current flows counterclockwise 4 53V and the current flows clockwise 22 41V and the current flows clockwise O 1 81V and the current flows counterclockwise

Consider the following electric circuit At a given through the battery is 2 A and increasing at a rate 1 A s The value of emf of the cell is assume the cell to be ideal moooo www 452 2H 0 4 V 02V 06V 0 10

Switch is in position 1 for a long time At time t 0 it is shifted to position 2 Find the maximum charge which will accumulate on capacitor E R LR E 2C R OLC E olm 2 C

RMS value of emf per turn 1 11 x 4f OM 4 44f OM This is called the emf equation of transformer which shows emf number of turns is same for both primary and secondary winding For an ideal transformer on no load EI VI and E2 V2 6 31 PM

The solenoid is at rest and is connected to a galvanometer If magnet A and B are moved towards the solenoid with the same velocity at the same time will there be any change i n the readings of galvanometer C and D wh ich are connected to extremely small part of the solenoid Further will there be any change in the galv anometer connected to the whole solenoid Magnet A SN Now 6 Magnet B F

he same 4 11 The straight wire AB carries a current I The ends of the wire subtend angles 0 and 0 at the point P as shown in e radii of figure 4 205 The magnetic field at the point Pis constant tion of posite A C Hol 4 B Hol 4 sin 0 sin 0 0 Figure 4 205 cos0 cos 0 0 P Hol B sin 0 sin 0 4 D Hol 4 cos0 cos 0

A current carrying length is placed at distance x from a rectangular conducting loop having side length a and b The mutual inductance of the given system is 1 Ha 2 b 2 A In Hb 3 In 2 Ha In 4 a x a x a X x a a a x ite b

In the given circuit the potential difference across resistance is 54 V and power consumed by it is 16 W If AC frequency is 60 Hz find the value of L 1 1 H 120V 60Hz R www 2 2 H 000000

A circular conduction loop of radius ro and having resistance per unit length as shown in the figure is placed na magnetic field B which is constant in space and time The ends of the loop are crossed and pulled in pposite directions with a velocity v such that the loop always remains circular and the radius of the loop goes n decreasing then A B C Radius of the loop changes with r as r ro vt n EMF induced in the loop as a function of time is E 2Bv ro vt n Bv Current induced in the loop is I 2 By

5 32 Two parallel wires AL and KM 250 m s earths connected by a resistor R and placed in a magnetic field B which is perpendicular to the plane containing the wire as Wb m2 shown in figure 5 340 Another wire CD now connects the two etween wires perpendicularly and made to slide with velocity v Calculate the workdone needed to slide the wire CD Neglect the resistance of all the wires gnetic tempt 5 338 www L D M

in uniform magnetic field B directed into the paperne questio Where AO and OC 2 then 41 A conducting rod AC of length 3 is rotated about O Xxxxx xxx xxxxxxxxx XXXXXXXXXXXX xx xxxx 50 B 2 1 VA Vcl 3 VA Vc 2B 2 VA Vcl 4 VA VC Telegram nequestio 30 B 2 Bo 2 1 2 2 4 1 5 2 5

Test 2 Code A 44 The current in the inductor is varying with time according to the plot as shown in figure Which one of the following is best variation of voltage with time in inductor 1 0 72 2 0 2 3 to All India Aakash Test Series for NEET 2021 f 45 The magnetic flux linked with a coil varies with time tas 4f 12t 7 where is in weber and fin 4 second The induced current is zero at time t equals 1 2 s 2 3 s A 2 3 0 5 s 4 1 5 s

hin flexible wire of length L is connected to two adjacent fixed points and carries a current in the clockwise direction as shown in the figure When the system is IBL t in a uniform magnetic field of strength 8 going into the plane of the paper the wire takes the shape of a circle If tension in the wire is then value of kis 3 swer O 01 x xx xx xx x xxx xxxxxxxx x xx xx xx x x xx xx xx x xxxxxxxx xx xx XXX xxxxxxxx 02 0 3 04 05 06 07 08 09 11 16 21 26 31 36 41 12 17 22 27 32 37 42 46 PP 13 18 23 28 33 38 43 P

38 A wire of length 2 is bent at mid point so that angle between the two half is 90 If it moves with velocity vas shown in figure inside the magnetic field B then the induced emf in the wire will be xPx x uestionpaper B 1 2B v P at higher potential and Q at lower potential El Foun 2 2B v P at lower potential and Q at higher potential 3 2B v P at higher potential and Q at lower potential 4 2B v P at lower potential and Q at higher potential ugh Work

The loop shown moves velocity v in a uniform magnetic field of magnitude B directed into the paper The potential difference between P and Q is e L 31 sub vh BLv 1 e 2 O 2 e BLv 2 3 e 0 4 e BLU L V staney B P Q L 2 83 Q is positive with respect to P P is positive with respect to Q

The adjoining figure shows two bulbs B and B resistor R and an inductor L When the switch Sis turned off www R eeeeeee L H B B S 1 Both B and B2 die out promptly 2 Both B and B2 die out with some delay 3 B dies out promptly but B2 with some delay

A conducting ring of radius r and resistance R is moving downward with a constant velocity v Let due to a fixed magnet axial magnetic field varies only with the axial 1 2 Tesla When the ring is at a height x from the north pole of the magnet distance x from north pole as Bx Tesla and the radial magnetic field varies as B TTX TTX the magnetic force experienced by the ring is ar v RX3 V B 0 X B

A square wire loop of side length L is made out of a uniform thin conducting wire The resistance of the loop is R The loop is placed in the X Y plane with its sides parallel to the coordinate axes and its centre at the origin The loop is pivoted to rotate without friction about the Y axis A uniform magnetic field of magnitude Bexists the Z direction At t 0 the loop is given an angular impulse Jabout the Y axis If the loop rotates by an angle 180 before it comes to rest and J X BI R then X is

There are two circular coils of equal areas and equal magnetic flux through them The resistances of the coils are in the ratio 1 2 If the magnetic flux through the coils is switched off then the ratio of the charges flown through the coils will be 2 1 1 3 4 1

A conducting rod of length 25 cm is free to slide on two parallel conducting bars as shown in the figure In addition two resistors 592 and 1092 are connected across the ends of the bars There is a uniform magnetic field 0 02 tesla pointing inside the plane of paper Suppose an external agent pulls the bar towards the left at a constant speed 5 ms A Current through 502 resistor is 5 mA B Current through 102 resistor is 10 mA C Force applied by agent to maintain constant 5 ms velocity is 20 N D Power delivered by external agent is 50 watt R xxxx B xx xxxxx XXXXX xx xx xx xx xx xx xx xx Sliding rod www

The magnitude of emf induced in a 2 mH inductor in which the current changes from 8 A to 6 A in 10 3 second is 2 x 10 6 V 8 x 10 6 V 4 V

In the circuit shown in the figure switch S is closed at t 0 Then which of the following statements is WRONG Given R L 20 A Initial current through the battery is s R B After a long time current through battery is 2R C D 5 The current in the battery is times its initial value at 8 R www 2R S t RC n2 The currents in the inductor and the capacitors are equal at t RC n3 C L 0000000 E

A rod is rotating with a constant angular velocity w about point O its cnetre in a magnetic field B as shown Which of the following figure correctly shows the distribution of charge inside the rod X X X X X X X X X X X X X X X x 8 x X B X X x x X X X X X X

A current carrying loop is dropped from the position as shown in figure The loop starts entering into a region of uniform magnet field directed into the plane Which of the following statements is correct Neglect effects of self induction and take g acceleration due to gravity A The loop will fall with an acceleration more than g The loop will fall with an acceleration less than g The magnitude of acceleration of loop will increase as it moves down X M

coil of inductance 0 2H and 192 resistance is connected to 90V source At what rate does the current in the coil grow at the instant the oil is connected to the source 450 As 4 5 As 45 As 1 0 45 As 1

5 16 A voltage source delivers 4A when the load connected is 502 and 2A when the load is 2002 what 50 and power transfer is the maximum power it can deliver power transfer efficiency with R efficiency when it delivers 50 W

9 7 A series RC circuit with R 102 has an impedance with an angle of 45 at fi 500 Hz Find the fre quency for which the magnitude of the impedance is a twice that at f b one half that at f

5 The primary and secondary coils of a transformer have 150 and 50 turns respectively If the magnetic flux linked with the primary coil is given by o 30t where is in webers t is in seconds and o is a constant the output voltage across the secondary coil is 0 1 190 V 3 20 V 2 10 V 4 90 L

3 9 A passive network contains resistors a 70 mH inductor and a 25 F capacitor Obtain respective 100 s domain impedances for a driving voltage a v cos 300t V 100 sin 300t 45 V b v 100e

Two conducting sphere of radius R are placed at a large distance from each other They are connected by a coil of inductance L as shown in the figure Neglect the resistance of the coil The sphere A is given a charge Q and the switch S is closed at time t 0 Time after charge Q TLR on Bis is 2 Then value of a is A R L mm S B R

A circular coil of radius 1 cm and 15 turns is rotated in a uniform magnetic field of 0 5 T with constant angular velocity of 300 rad s about its diameter as axis The resistance of coil is 9 Q and self inductance is negligible Assume at t 0 the plane of loop is parallel to magnetic field an axis of rotation is perpendicular to the field lines The induced current in the loop is 1 7 cos 300t mA 25 cos 300t mA O 0 08 sin 300t mA 225 sin 300 mA

2 7 A series circuit with R 2 52 L 2 mH and C 500 F has a current which increases lin early from zero to 10 A in the interval 0 1 ms remains at 10 A for 1 ms t 2 ms and decreases linearly from 10 A at t 2 ms to zero t 3 ms Sketch Up U and vc

39 A metallic rod of length lis hinged at the point M and is rotating about an axis perpendicular to the plane of paper with a constant angular velocity o A uniform magnetic field of intensity Bis acting in the region as shown in the figure parallel to the plane of paper The potential difference between the points M and N a is always zero 1 c is always Bool M 140 N B b varies between Bol to 0 d is always Bol

In a uniform magnetic field of induction B a wire in the form of a circle of radius r rotates about the diameter of the circle with angular frequency w The axis of rotation is perpendicular to the field If the total resistance of the circuit is 2R the maximum power generated is

A ring of radiusir is spun about its axis with an angular velocity w in a horizontal plane A uniform magnetic field of magnitude 8 exists in the region in vertical direction the end induced in the ring is 0 2 3 4 Zero mr wB V2 82 Bru

In the figure shown a conducting rod of length 1 resistance R and mass m can move vertically downward due to gravity Other components are fixed Inward uniform magnetic field B is present AB CD are smooth vertical conducting rails If the rod is released from rest then B X X X X X X X X X X C Acceleration of rod becomes constant after long time Acceleration of rod decreases with time and becomes zero at infinity After long time charge on capacitor is constant Terminal velocity of rod is mg 8212