Question

Which metal is a good conductor of heat?
A. Gold
B. Mercury
C. Lead
D. Alloys

Answer 1

Hint: Any substance that can conduct heat from the heated end of the substance to the cooler of the substance is a good conductor of heat. Any substance that cannot conduct heat from the heated end of the substance to the cooler of the substance is a good conductor of heat. Metals are considered as good conductors of heat whereas the non-metals are considered as the poor conductor of heat.

Complete solution:
We know, heat is conducted in a substance from one end to another when the particles of the substance vibrate. Due to this vibration, kinetic energy is passed from one particle to the other. In metals, there are free electrons which makes the energy transfer easy. Thus, metals are good conductors of heat. Gold, mercury, lead and alloys all are good conductors of heat. But compared to other metals, gold is a good conductor of heat.

So, the correct answer is option A i.e. gold.

Additional Information:
When a metal is heated, a free electron collides with a free electron in the hot end of the metal and gains kinetic energy. This electron moves to the colder end of the metal with high kinetic energy and collides with a cold ion in the colder region. In this way, the cold ion becomes hot. Then this hot ion vibrates and the process repeats to make the cold end hot. This way, energy is transferred from the hot end to cold end of a metal.

Note:
Students must know that silver is considered as the best conductor of heat. Even though silver is considered as the best conductor of heat, copper and gold are used more often because copper is less expensive and gold has higher corrosion resistance. The thermal conductivity of the metal depends on the material structure, density of the material, moisture content, temperature and the pressure of the operating condition.