In the given figure, potential difference between \(A\) and \(B\) is:

1. 0
2. \(5~\mathrm{V}\)
3. \(10~\mathrm{V}\)
4. \(15~\mathrm{V}\)

In the given figure what will be the coefficient of mutual inductance?

1. \(\frac{\mu_0a}{2\pi}in\Big(1+\frac{a}{2b}\Big)\)
2. \(\frac{\mu_0a}{\pi}in\Big(1+\frac{b}{2a}\Big)\)
3. \(\frac{\mu_0a}{2\pi}in\Big(1+\frac{a}{b}\Big)\)
4. \(\frac{\mu_0a}{2\pi}in\Big(1+\frac{b}{a}\Big)\)

A metal rod at a temperature of \(145^\circ\mathrm{C}\), radiates energy at a rate of \(17~\mathrm{W}\). If its temperature is increased to \(273^\circ\mathrm{C}\), then it will radiate at the rate of:
1. \( 49.6 \mathrm{~W} \)
2. \( 17.5 \mathrm{~W} \)
3. \( 50.3 \mathrm{~W} \)
4. \(67.5 \mathrm{~W}\)
 

A square wire of side \(2.0~\mathrm{cm}\) is placed \(20~\mathrm{cm}\) in front of a concave mirror of focal length \(10~\mathrm{cm}\) with its centre on the axis of the mirror and its plane normal to the axis. The area enclosed by the image of wire is:
1. \( 7.5 \mathrm{~cm}^2 \)
2. \( 6 \mathrm{~cm}^2 \)
3. \(2 \mathrm{~cm}^2 \)
4. \( 4 \mathrm{~cm}^2\)
 

A lead bullet penetrates into a solid and melts. Assuming that \(50\%\) of its kinetic energy was used to heat it, the initial speed of the bullet is: (the initial temperature of the bullet is \(25^\circ\mathrm{C} \) and its melting point is \(300^\circ\mathrm{C} \)). Latent heat of fusion of lead \(=2.5\times10^4~\mathrm{J/Kg}\) and specific heat capacity of lead \(=125~\mathrm{J/Kg-K}\).
1. \( 100 \mathrm{~m} / \mathrm{s} \)
2. \( 490 \mathrm{~m} / \mathrm{s} \)
3. \( 520 \mathrm{~m} / \mathrm{s} \)
4. \( 360 \mathrm{~m} / \mathrm{s}\)