According to Joule's law of heating, the heat produced in any resistor is inversely proportional to the resistance of the resistor.

In the following circuits, the heat produced in the resistor or combination of resistors connected to a $12 \mathrm{V}$ battery will be

The working of an electric heater depends on:

In an electrical circuit, two resistors of $2 \mathrm{\Omega }$ and $4 \mathrm{\Omega }$ respectively are connected in series to a $6 \mathrm{V}$ battery. The heat dissipated by the $4 \mathrm{\Omega }$ resistor in $5 \mathrm{s}$ will be

Unit of electric power may also be expressed as_____.