or is O 1 Clockwise and increasing with time 2 Clockwise and decreasing with time 3 Anti clockwise and increasing with time 4 Anti clockwise and decreasing with time 28 The magnetic flux through a coil of resistance 10 22 t 3 3 2 current in the circuit is zero at 1 t 2 unit 3 t 4 unit 29 When a bar magnet falls through a long hollow metal cylinder fixed with its axis vertical then acceleration of the magnet when it is accelerating will be 1 Zero 3 Less than g current varies as in weber 12 10t 5 The 2 t 5 unit 4 t 0 unit 2 More than g 4 Equal to g 30 The maximum mutual inductance of the two coils is 8 H One of the coil has a self inductance of 16 H Then the self inductance of the other coil is 1 8 H 2 16 H 4 2 H 3 4 H 31 A magnetic flux of 500 Wb per turn passing through a 200 turns coil is reversed in direction in 20 x 10 3 second The average emf induced in the coil is 2 5 V 4 75 V 1 2 5 V 3 10 V 32 A straight conductor of length 2 0 m is moving with speed 2 m s perpendicular to a uniform magnetic field of induction 1 0 T The induced emf across the ends of the conductor is 1 2 volt 2 4 volt 4 Zero 3 8 volt the 33 The circular wire loop of radius R is placed x z plane with the centre at the origin Another circular loop of radius r r R having 32 turns is placed with its centre at y 3R The plane of the 34 0 1 Hor R H r 3 4 TR H R The periphery of an insulating disc of radius R and mass M is charged uniformly and has linear charge density The disc is rotating freely with constant angular velocity about a vertical axis as shown Uniform magnetic field B extends over entire circular region of disc pointing downward If the magnetic field is switched off then find the value of Bo for which the disc stops 1 H r R 40 M TAR w M R 1 m g 28 2R 2 2m P 00 2 3 4 0 35 A conducting rod of length 1 mass m and of negligible resistance slides without friction on two parallel vertical conducting rails connected at the top through a resistor of resistace R The rails are also of negligible resistance A uniform magnetic field Bo exists perpendicular to the plane of the rails pointing inward After a long time the heat dissipated in the resistor per second is B 200 M R co M 2 R www R m g R B 1 m 0