The bulb gets hot. The bulb produces light. The lamp uses copper wires. The lamp can be turned off at a switch.
I gave my students this multiple choice question: Every night, Johnny reads next to a lamp that is lit by an incandescent light bulb. Which is the best indication that the transfer of electrical energy to the lamp is inefficient?

Only one answer is correct among these 4 choices:
- The bulb gets hot.
- The bulb produces light.
- The lamp uses copper wires.
- The lamp can be turned off at a switch.

Could you tell me which one is correct?

The bulb gets hot.