The poorest conductor of heat among the following is
- Acopper
- Blead
- Cmercury
- Dzinc
- ENone of the above / More than one of the above
Show answer and explanation
Correct answers: (b) lead or (c) mercury
Explanation
Metals conduct heat mainly through free electrons. Copper (about 400 W/m·K) and zinc (about 116 W/m·K) are good conductors.
Lead (about 35 W/m·K) is a poor conductor, but mercury (about 8.3 W/m·K) is poorer still, so strictly mercury is the poorest of the four.
The answer key gives (b) lead; both (b) and (c) are accepted here.