Question

Thermal conduction takes place in:
(A) Solid, liquid
(B) Liquid, gas
(C) Gas, solid
(D) Solid, liquid, gas

Answer 1

Hint: All three phases of matter viz. solid, liquid and gas have particles which are bound by attractive forces. Thermal conduction is the transfer of internal energy by collision of particles within a body.

Complete step by step answer:
Conduction is one of the three ways for transfer of heat energy. It is the process by which heat energy is transferred through collisions between neighbouring atoms, molecules or electrons.
Heat spontaneously flows from a hotter to colder body. The rate of flow of heat energy by conduction is higher when there is a large temperature difference between one part of the body and any other part.
We know that all three phases of matter, i.e., solid, liquid and gas consists of atoms, molecules or ions.
The attractive forces between particles decreases in the order: solid > liquid > gas
The particle to particle distance increases in the order: solid < liquid < gas
Therefore, the rate of energy transfer by conduction decreases in the order: solid > liquid > gas
In solids, conduction is propagated by the combination of vibrations and collisions of molecules, and of collisions of free electrons. In gases and liquids, conduction is due to collisions of molecules during their random motion.

Hence, the correct option is (C).

Note: Though, the particle distances between gases are much more in comparison to solids and liquids, conduction slowly occurs in gases also. One such example is the conduction of heat in atmospheric air.