When the balance point is obtained in the potentiometer, a current is drawn from

$B_1, B_2$ and $B_3$ are three identical bulbs connected as shown in Figure 12.8. When all the three bulbs glow, a current of 3A is recorded by the ammeter A.

How much power is dissipated in the circuit when all the three bulbs glow together?

Heat energy is being produced in a resistance in a circuit at the rate of $100\ W$. The current of $2\ A$ is flowing in the circuit. what must be the value of the resistance (in $\Omega$)?

The resistance of the filament of an electric bulb changes with temperature. If an electric bulb rated $220 \ V$ and $100 \ W$ is connected to $(220\times 0.8) \ V$ source, then the power would be :