Final answer:
The heat emitted by lamps does not affect their efficiency.
Step-by-step explanation:
The heat emitted by lamps does not affect their efficiency.
Efficiency is a measure of how well an object or system converts input energy into useful output energy. In the case of lamps, the efficiency is determined by the ratio of light output to the electrical input energy. The heat emitted by lamps is considered waste energy, as it is not useful for the intended purpose of providing light.
Therefore, option C) No effect on efficiency is the correct answer.