Figure shows a uniform magnetic field B confined to a cylindrical volume and is increasing at a constant rate. The instantaneous acceleration experienced by an electron placed at P is:

     

1. zero

2. towards right

3. towards left

4. upwards

A conducting wire frame is placed in a magnetic field which is directed into the plane of the paper (see figure). The magnetic field is increasing at a constant rate. The directions of induced currents in wires AB and CD are

1. B to A and D to C

2. A to B and C to D

3. A to B and D to C

4. B to A and C to D

Two identical conductors \(P\) and \(Q\) are placed on two frictionless (conducting) rails \(R\) and \(S\) in a uniform magnetic field directed into the plane. If \(P\) is moved in the direction as shown in the figure with a constant speed, then rod \(Q\):

Two circular coils A and B are facing each other as shown in figure. The current i through A can be altered. Then-

1. there will repulsion between A and B if i is increased

2. there will be attraction between A and B if i is increased

3. there will be neither attraction nor repulsion when i is changed

4. attraction or repulsion between A and B depends on the direction of current. It does not depend whether the current is increased or decreased.

The e.m.f. induced in a coil of wire, which is rotating in a magnetic field, does not depend on:

1. the angular speed of rotation

2. the area of the coil

3. the number of turns on the coil

4. the resistance of the coil

A bar magnet is moved along the axis of copper ring placed far away from the magnet. Looking from the side of the magnet, an anticlockwise current is found to be induced in the ring. Which of the following may be true?

1. The south pole faces the ring and the magnet moves towards it.

2. The north pole faces the ring and the magnet moves towards it.

3. The north pole faces the ring and the magnet moves away from it.

4. None of the above

For L-R circuit, the time constant is equal to:

1. twice the ratio of the energy stored in the magnetic field to the rate of the dissipation of energy in the resistance.

2. the ratio of the energy stored in the magnetic field to the rate of dissipation of energy in the resistance.

3. half of the ratio of the energy stored in the magnetic field to the rate of dissipation of energy in the resistance.

4. square of the ratio of the energy stored in the magnetic field to the rate of dissipation of energy in the resistance.

Coefficient of mutual inductance for the given coils does not depend on :

1. their relative orientation

2. their geometry

3. Rate at which current changes in the coil

4. the medium in which the coil lies

An L-R circuit is connected to a battery  at t=0. Which of the following quantities is not zero just after the circuit is formed?

1. current in the circuit

2. magnetic field energy in the inductor

3. power delivered by the battery

4.  emf induced in the inductor.