A 10 H inductor carries a current of 20 A. How much ice at 0°C could be melted by the energy stored in the magnetic field of the inductor?
Latent heat of ice is  2.26 × ${10}^3$ J/kg .

1.	0.08 kg	2.	8.8 kg
3.	0.88 kg	4.	0.44 kg

A copper rod of mass \(m\) slides under gravity on two smooth parallel rails \(l\) distance apart and set at an angle \(\theta\) to the horizontal as shown in fig. At the bottom, the rails are joined by a resistance \(R\). There is a uniform magnetic field perpendicular to the plane of the rails. The terminal velocity of the rod is:

1. \(\frac{m g R \cos \theta}{B^{2} l^{2}}\)

2. \(\frac{m g R \sin \theta}{B^{2} l^{2}}\)

3. \(\frac{m g R \tan \theta}{B^{2} l^{2}}\)

4. \(\frac{m g R \cot \theta}{B^{2} l^{2}}\) 

Some magnetic flux is changed from a coil of resistance \(10~\Omega\)$\mathrm{}$. As a result, an induced current is developed in it, which varies with time as shown in the figure. The magnitude of change in flux through the coil in Wb is:

In the circuit diagram shown in figure, R = 10 \(\Omega\), L = 5 H, E = 20 V and i = 2 A. This current is decreasing at a rate of 1.0 A/s. $V_{ab}$ at this instant will be:

A \(1~\text{m}\) long metallic rod is rotating with an angular frequency of \(400~\text{rad/s}\)$$ about an axis normal to the rod passing through its one end. The other end of the rod is in contact with a circular metallic ring. A constant and uniform magnetic field of \(0.5~\text{T}\) parallel to the axis exists everywhere. The emf induced between the center and the ring is:
1. \(200~\text{V}\)
2. \(100~\text{V}\)
3. \(50~\text{V}\)
4. \(150~\text{V}\)

Current in a circuit falls from \(5.0\) A to \(0\) A in \(0.1\) s. If an average emf of \(200\) V is induced, the self-inductance of the circuit is:
1. \(4\) H
2. \(2\) H
3. \(1\) H
4. \(3\) H

The radius of a loop as shown in the figure is \(10~\text{cm}.\) If the magnetic field is uniform and has a value \(10^{-2}~ \text{T},\) then the flux through the loop will be:
 

If a current is passed through a circular loop of radius \(R\) then magnetic flux through a coplanar square loop of side \(l\) as shown in the figure \((l<<R)\) is:

1. \(\frac{\mu_{0} l}{2} \frac{R^{2}}{l}\)

2. \(\frac{\mu_{0} I l^{2}}{2 R}\)

3. \(\frac{\mu_{0} l \pi R^{2}}{2 l}\)

4. \(\frac{\mu_{0} \pi R^{2} I}{l}\)

The magnetic flux linked with a coil varies with time as \(\phi = 2t^2-6t+5,\) where \(\phi \) is in Weber and \(t\) is in seconds. The induced current is zero at:
1. \(t=0\)
2. \(t= 1.5~\text{s}\)
3. \(t=3~\text{s}\)
4. \(t=5~\text{s}\)

Eddy currents are used in:

1. Induction furnace

2. Electromagnetic brakes

3. Speedometers

4. All of these