Why the torch bulb does not glow when the switch is turned off?

The torch bulb does not glow when the switch is turned off, because the switch open, breaks, or disconnect,  the circuit inside the torch.

The torch bulb produces light when the positive and negative terminals of the dry cells are connected to the bulb, and the switch is moved to the on position. The current travels from the positive terminal through the bulb and returns back via the negative terminal, making a complete circuit.

But, when the switch is moved to the off position, a metal piece inside the case disconnects or breaks the positive terminal of the battery, and the circuit gets incomplete.