Question

Which of the following is a good conductor of heat?
A. Plastic
B. Water
C. Glass
D. Copper

Answer 1

Hint: A good conductor of heat is any substance that can conduct heat from its heated end to the cold end as quickly as possible. There are many conductors of heat and they are arranged in the order of their thermal conductivity.

Complete answer:
We know that heat is conducted when particles vibrate and pass kinetic energy from one particle to another.
In metals there are free electrons. Hence these free electrons can also transfer the kinetic energy which increases the rate of energy transfer.
Hence, as we know, metals are very good conductors of heat.
Copper is a metal and copper has many free electrons in it.
Therefore copper is a good conductor of heat.

So, the correct answer is “Option D”.

Additional Information:
When we say copper is a good conductor of heat, it means that if we heat one end of a copper rod, the other end of the rod will spontaneously rise to the same temperature.
When a piece of copper is heated, a free electron collides with a free electron in the hot end of the copper piece and gains kinetic energy.
This electron moves to the colder end with high kinetic energy and collides with a cold ion in the colder region. Thus the cold ion, which is hot now, vibrates and the process repeats to make the cold end hot.
In this way energy is transferred from hot region to cold region of a piece of copper.

Note:
Copper is a metal that has high thermal conductivity and a high melting point. Copper also does not undergo corrosion.
Hence copper is used in many heating appliances.
Stainless steel has a resistance to corrosion similar to copper. But the thermal conductivity of stainless steel is very less compared to that of copper.
Therefore copper is preferred in heating applications.
Some of the applications are,
Copper plates are used for saucepan bottoms; copper pipes are used in car radiators, hot water tanks etc.