Question

Which of the following statements is true about the electric field in side the bulb filament ?

• A. The field must be zero because the filament is made of metal.
• B. The field must be zero because a current is flowing.
• C. The field must be zero because any excess charges are on the surface of the filament.
• D. The field must be non-zero because the flowing current produces an electric field.
• E. The field must be non-zero because no current will flow with out an applied field.

Answer 1

The correct option is E The field must be non-zero because no current will flow with out an applied field.

In side of bulb filament Electric field is non-zero because there is a continuous flow of electrons through it which heats up the filament. This flow is due to potential difference and thus electric field is also present due to this potential difference.