If the work done in blowing a soap bubble of volume ' V ' is ' W ', then the work done in blowing a soap bubble of volume ' 2 V ' will be

A coil has inductance H . The ratio of its reactance when it is connected first to an a.c. source and then to d.c. source is

A particle of mass m collides with another stationary particle of mass $M$. The particle $m$ stops just after collision. The coefficient of restitution is

In the circuit shown in the following figure, the potential difference cross $3 \mu \mathrm{~F}$ capacitor is