Explain why the potential difference across the terminals of a cell is more in open circuit and it is reduced in the closed circuit.

Figure shows a circuit diagram having a battery of $24 \mathrm{V}$ and negligible internal resistance. Calculate:

$E=V=24 \mathrm{V}$

(i) Reading  of ammeter.
(ii) Reading  of$V_1, V_2 and V_3$.

In the given figure, the lightning arrangement is protected by $3 \mathrm{A}$ fuse.

(i) When the $200 \mathrm{W}$ lamp $\text{'}\mathrm{A}\text{'}$ is switch on, what current does it draw?

In the given figure, the lightning arrangement is protected by $3 \mathrm{A}$ fuse. What current flows through the fuse when all the lamps are switched on?

In the given figure, the lightning arrangement is protected by $3 \mathrm{A}$ fuse. How many units of energy will the system consume, if all the lamps are on for $20$ hours?

In the given figure, the lightning arrangement is protected by $3A$ fuse. What would happen, if all the lamps were replaced by $200 \mathrm{W}$ lamps and they all are switch on?

 Which electric bulb has greater heat production, a $100 \mathrm{W}$ or a $200 \mathrm{W}$? Assume that both of them are connected to the same supply.