In the given circuit, the potential difference across the plates of the capacitor $C$ in steady state is

The potential difference across a conducting wire of length 20 cm is 30 V . If the electron mobility is $2 \times 10^{-6} \mathrm{~m}^2 \mathrm{~V}^{-1} \mathrm{~s}^{-1}$, then the drift velocity of the electrons is

A maximum current of 0.5 mA can pass through a galvanometer of resistance $15 \Omega$. The resistance to be connected in series to the galvanometer to convert it into a voltmeter of range $0-10 \mathrm{~V}$ is

Two charged particles of specific charges in the ratio 2:1 and masses in the ratio $1: 4$ moving with same kinetic energy enter a uniform magnetic field at right angles to the direction of the field. The ratio of the radii of the circular paths in which the particles move under the influence of the magnetic field is