Question

In which of the following electric circuits does the electric bulb shown glow?

• A.

  

• B.

  

• C.

  

• D.

  

Answer 1

The correct option is C

The explanation for the correct option:

Option C

1. The bulb will glow in option (c) as the circuit is closed and the presence of silk thread does not intervene in the flow of electrons in the circuit.
2. Any obstruction in the path of the electrons due to the presence of a conductor deviates the current from the original path resulting in an open circuit.
3. But silk thread is an insulator. Hence it does not obstructs the current flow.

The explanation for the incorrect option

Option (A)

It is an open circuit as the plug key is in open condition.

Option (B)

1. The electrons get deviated from the path and flow through the silver wire.
2. This is short-circuited connection.

Option (D)

1. Silver wire is a good conductor of electricity.
2. Hence the bulb will glow

Hence option C is correct.