A lamp contains a metal filament that emits light when an electric current heats it. The centre of the filament reaches a very high temperature. The filament ends are attached to the lamp base and are at a lower temperature. Which statement is correct?
- ASome thermal energy is conducted to the base of the lamp.
- BThe filament radiates energy equally at all points along its length.
- CThe lamp transfers all of the input energy as visible light.
- DWhen the potential difference (p.d.) across the filament is halved, the power output is halved.