An electric kettle takes $4 \ A$ current at $220 \ V$. If the entire electric energy is converted into heat energy, then the time (in minutes) taken to increase the temperature of $1 \ kg$ of water from $34^{\circ} C$ to $100^{\circ} C$ is

$A$ $100\, W$ bulb working on $200\, V$ and a $200\, W$ bulb working on $100\, V$ have:

$A$ $10\, \Omega$ electric heater operates on a $110\, V$ line. Calculate the rate at which it develops heat in $watts$.

$A$ potential $V_0$ is applied across a uniform wire of resistance $R$. The power dissipation is $P_1$. The wire is then cut into two equal halves and a potential of $V_0$ is applied across the length of each half. The total power dissipation across two wires is $P_2$. The ratio $P_2: P_1$ is $\sqrt{x}: 1$. The value of $x$ is $.............$.

$4$ bulbs marked $40\, W, 250\, V$ are connected in series with a $250\, V$ mains. The total power consumed is ............. $W$.

What amount of heat will be generated in a coil of resistance $R$ due to a charge $q$ passing through it if the current in the coil decreases to zero uniformly during a time interval $\Delta t$?