Question

Describe an experiment to show that electricity flows only if the circuit is complete and it does not flow if the circuit is incomplete.

Answer 1

Take two torch bulbs A and B. Connect them to a cell through a switch as shown in fig. The bulbs are said to be in series. Close the switch (i.e., the circuit it completed), you will see that both the bulbs glow.

Circuit is complete, both bulbs glow

Now take out the connection of the bulb B as shown in fig. Now close the switch, you will observe that bulb A does not glow, because the circuit is now incomplete.

Circuit is incomplete, bulb A does not glow

Now replace bulb B by a fused bulb fig. and close the switch. Again you will see that bulb A does not glow. This is because the circuit being in series is still incomplete.

Incomplete circuit, bulb A does not glow

Thus, when appliances are in series, they are dependent on each other.