Question

Nikhil has set up an electric circuit using some connecting copper wires, two cells, a switch and a bulb that he has taken from a torchlight. But after connecting all the components, the bulb is not glowing. What can be the possible reason(s) for this?
(i) The cells are dead.​
(ii) The circuit is open.​
(iii) The switch is closed.​
(iv) The connection between the terminals of the cells is not proper.​

• A.
  (i) and (ii) only
• B.
  (i), (ii), and (iv)
• C.
  (i), (ii), and (iii)
• D.
  (i), (ii), (iii), and (iv)

Answer 1

The correct option is B

(i), (ii), and (iv)
A simple electric circuit can be constructed using copper wires, a battery, a switch and an electric bulb. Few possible reasons why Nikhil has been failing to make the bulb glow are:

The battery is an old one, hence it might be dead.
The circuit is open. So, no current flows in the circuit. Thus, bulb will not glow.

When a switch is connected in a circuit and it is closed that means the current is flowing in the circuit. Thus in this case the bulb can glow.

If the positive or negative terminals of two cells are connected to each other then the cells will not work. The positive terminal of one cell should be connected to negative terminal of other cell.