An ideal inductor is connected across a capacitor. Oscillations of energy $K$ are set up in the circuit. The capacitor plates are slowly drawn apart such that the frequency of oscillations is quadrupled. The work done in the process is

If $R$ and $L$ denote resistance and inductance of a material, then the dimension of $L R$ will be:

A bulb of resistance 280 Ohm is supplied with a voltage $\mathrm{V}=400 \sin \pi \mathrm{t}$. The peak current is

An LCR series ac circuit is at resonance with 10 V each across $\mathrm{L}, \mathrm{C}$ and R . If the resistance is halved, the respective voltage across $R, C$ and $L$ are