What is the dimensional formula of magnetic flux?

1. $[\mathrm{M}$ ${\mathrm{L}}^2$ ${\mathrm{T}}^{-2}$ ${\mathrm{A}}^{-1}]$

2. $[\mathrm{M}$ ${\mathrm{L}}^1$ ${\mathrm{T}}^{-1}$ ${\mathrm{A}}^{-2}]$

3. $[\mathrm{M}$ ${\mathrm{L}}^2$ ${\mathrm{T}}^{-3}$ ${\mathrm{A}}^{-1}]$

4. $[\mathrm{M}$ ${\mathrm{L}}^{-2}$ ${\mathrm{T}}^{-2}$ ${\mathrm{A}}^{-2}]$

A cylindrical magnet is kept along the axis of a circular coil. On rotating the magnet about its axis, the coil will have induced in it:

The magnetic flux through a coil varies with time t as shown in the diagram. Which graph best represents the variation of the e.m.f. E induced in the coil with time t?

1.		2.
3.		4.

A bar magnet is made to fall through a long surface copper tube. The speed (v) of the magnet as a function of time (t) is best represented by:

When a conducting wire XY is moved towards the right, a current flows in the anti-clockwise direction. Direction of magnetic field at point O is:

Eddy currents are induced when:

1. A metal block is kept in a changing magnetic field.

2. A metal block is kept in a uniform magnetic field.

3. A coil is kept in a uniform magnetic field.

4. Current is passed in a coil.

The magnetic energy stored in a long solenoid of an area of cross-section A in a small region of length L is:

1. $\frac{{\mathrm{B}}^2\mathrm{AL}}{2{{\mathrm{\mu }}_0}^2}$

2. $\frac{\mathrm{AL}}{2{\mathrm{\mu }}_0}$

3. $\frac{1}{2}{\mathrm{\mu }}_0{\mathrm{B}}^2\mathrm{AL}$

4. $\frac{{\mathrm{B}}^2\mathrm{AL}}{2{\mathrm{\mu }}_0}$

An inductor is connected to a direct voltage source through a switch. Then:

A long solenoid has self-inductance L. If its length is doubled keeping total number of turns constant, then its new self-inductance will be:

1. $\frac{\mathrm{L}}{2}$

2. 2L

3. L

4. $\frac{\mathrm{L}}{4}$

With the decrease of current in the primary coil from 2 A to zero in 0.01 s, the e.m.f. generated in the secondary coil is \(1000~\mathrm{V}\). The mutual inductance of the two coils is:

1. 1.25 H

2. 2.50 H

3. 5.00 H

4. 10.00 H