Connect a circuit on a wooden plank or on a thermocol sheet as shown in Figure. Insert two drawing pins at A and B. Insert a safety pin in between A and B. such that one end of the pin is completely in contact with B and the other end is left free. Now observe the bulb.What do you notice?What happens?Why doesn’t the bulb glow when the safety pin is left free at one end?

Connect a circuit on a wooden plank or on a thermocol sheet as shown i

1.	Connect a circuit on a wooden plank or on a thermocol sheet as shown in Figure. Insert two drawing pins at A and B. Insert a safety pin in between A and B. such that one end of the pin is completely in contact with B and the other end is left free. Now observe the bulb.What do you notice?What happens?Why doesn’t the bulb glow when the safety pin is left free at one end?
Answer» The bulb does not glow. Now touch the safety pin to pin A and observe the bulb again. The bulb glows. In this activity, the safety pin is used to close /open the circuit. When the safety pin is left free at one end, the circuit is open. So the bulb doesn’t glow.