Which of the following is a poor conductor of electricity?

The chapter states that metals are generally good conductors of heat and electricity, but among metals, conductivity varies. It explicitly notes: "The best conductors of heat are silver and copper. Lead and mercury are comparatively poor conductors of heat." The same relative ordering carries over to electrical conductivity, since good thermal conductors (free electrons enabling heat transfer) are also good electrical conductors.

• (A) Pb — Correct. Lead is explicitly named in the text as a comparatively poor conductor (of heat, and correspondingly of electricity) among common metals.
• (B) Cu — Incorrect. Copper is named as one of the best conductors of heat and is used for electrical wiring precisely because it conducts electricity very well.
• (C) Ag — Incorrect. Silver is named as the best conductor of heat among metals and is also the best electrical conductor.
• (D) Al — Incorrect. Aluminium is a good conductor of electricity (used in wires and for making cooking vessels/anodising) and is not identified in the text as a poor conductor.

Hence lead (Pb) is the poor conductor among the given options.