Single correct · +4 / −1

Most good thermal conductors are also:

  1. (a) good electrical conductors
  2. (b) good electrical insulators
  3. (c) semiconductors
  4. (d) superconductors
Answer and solution

Answer (a) good electrical conductors

Solution

Physics sir · 4 steps

The same free electrons that carry charge also carry heat, so good at one means good at the other.

  1. Who carries heat. In a metal, heat is carried mainly by free electrons that move through the lattice and share their energy quickly. Lattice vibrations help too, but they are much slower.
  2. Who carries charge. Electric current in a metal is the drift of exactly the same free electrons. A material rich in free electrons is therefore good at both jobs.
  3. The link. The Wiedemann–Franz law states this for metals: the ratio of thermal to electrical conductivity, K/σ, is proportional to T. Silver, copper and aluminium top both lists.
  4. So. Most good thermal conductors are also good electrical conductors, option (a).

The idea to keep. Free electrons do double duty in metals, carrying both heat and charge. Diamond is the famous exception: it conducts heat through lattice vibrations, yet is an electrical insulator.

Answer from the NTA final answer key. Solution by PrepWiser.

Study Heat Transfer

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