An aluminium ring B faces an electromagnet A. If the current I through A can be altered, then:

1.	whether I increases or decreases, B will not experience any force.
2.	if I decreases, A will repel B.
3.	if I increases, A will attract B.
4.	if I increases, A will repel B.

A conducting wire is moving towards the right in a magnetic field B. The direction of the induced current in the wire is shown in the figure. The direction of the magnetic field will be:

The magnitude of the earth’s magnetic field at a place is B₀ and the angle of dip is δ. A horizontal conductor of length l lying along the magnetic north-south moves eastwards with a velocity v. The emf induced across the conductor is:
1. Zero
2. B₀lv sinδ
3. B₀lv
4. B₀lv cosδ

Two circuits have coefficient of mutual induction of 0.09 henry. Average e.m.f. induced in the secondary by a change of current from 0 to 20 ampere in 0.006 second in the primary will be:
1. 120 V
2. 80 V
3. 200 V
4. 300 V

In the figure magnetic energy stored in the coil is:

Consider the situation shown in the figure. The wire AB is sliding on the fixed rails with a constant velocity. If the wire AB is replaced by semicircular wire, the magnitude of the induced current will:

A circular loop of radius R carrying current i lies in the x-y plane. If the centre of the loop coincides with the origin, then the total magnetic flux passing through the x-y plane will be:

A uniform but time-varying magnetic field B(t) exists in a circular region of radius a and is directed into the plane of the paper, as shown. The magnitude of the induced electric field at point P at a distance r from the centre of the circular region:

1. is zero
2. decreases as $\frac{1}{r}$
3. increases as r
4. decreases as $\frac{1}{r^2}$

Two circular coils can be arranged in any of the three situations shown in the figure. Their mutual inductance will be:

A conducting rod of length 2l is rotating with constant angular speed $\omega$ about its perpendicular bisector. A uniform magnetic field $\overrightarrow{B}$ exists parallel to the axis of rotation. The e.m.f. induced between the two ends of the rod is:

1. \(B\omega l^2\)
2. $\frac{1}{2}B\omega l^2$
3. $\frac{1}{8}B\omega l^2$
4. Zero