An electric fan and a heater are marked as $100 \ W, 220 \ V$ and $1000 \ W, 220 \ V$ respectively. The resistance of the heater is

$A$ resistor dissipates $192 \, J$ of energy in $1 \, s$ when a current of $4 \, A$ is passed through it. Now,when the current is doubled,the amount of thermal energy dissipated in $5 \, s$ is $..... \, J$.

How many electrons per second flow through a filament of a $120 \ V$,$60 \ W$ electric bulb?

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

$A$ heater of $220\, V$ heats a volume of water in $5\, \text{min}$ time. $A$ heater of $110\, V$ heats the same volume of water in ............... $\text{min}$.

If a wire of resistance $20\,\Omega$ is covered with ice and a voltage of $210\,V$ is applied across the wire,then the rate of melting of ice is .................. $g/s$. (Take latent heat of fusion of ice $L = 80\,cal/g$ and $1\,cal = 4.2\,J$)