In the figure shown the power generated in $y$ is maximum when $y = 5\,\Omega $. Then $R$ is

A coil takes $15\,\min$ to boil a certain amount of water, another coil takes $20\,\min$ for the same process. Time taken to boil the same amount of water when both coil are connected in series ........... $min$

A $60\, watt$ bulb operates on $220\,V$ supply. The current flowing through the bulb is

By what percentage will the illumination of the lamp decrease if the current drops by $20 \%$ ?

Two bulbs one of $200$ $\mathrm{volts},$ $60$ $\mathrm{watts}$ and the other of $200$ $\mathrm{volts},$ $100$ $\mathrm{watts}$ are connected in series to a $200$ $\mathrm{volt}$ supply. The power consumed will be ................ $\mathrm{watt}$

The figure shows three circuits $I, II$ and $III$ which are connected to a $3\,V$ battery. If the powers dissipated by the configurations $I, II$ and $III$ are $P_1 , P_2$ and $P_3$ respectively, then