Question

Bad conductor heat is
(a). Copper
(b). Steel
(c). Silver
(d). None

Answer 1

- Hint: Conduction is a process of transfer of heat from one point to another. The body, which helps in this heat transferring process, is called a conductor. Compare the coefficient of thermal conductivity of the given materials.

Complete step-by-step solution -
Conduction of heat is the process of transmission of heat energy in which the heat is transferred from one particle to other particle without dislocation of the particle from their equilibrium position. Conduction is a process, which is possible in all states of matter. In solids only conduction takes place in non-metallic solids and fluids the conduction takes place only due to vibration of molecules, therefore they are poor conductors. In metallic solids, free electrons carry the heat energy. Therefore, they are good conductors of heat.
The conductivity of material depends on its coefficient of conductivity (K). Higher the value coefficient of conductivity better is the conductivity of that material. For perfect conductors, the value of K is infinity and for perfect insulators, K is zero.
The value of K for copper is 385 WK/m.
The value of K for steel is 50.2 WK/m.
The value of K for silver is 406 WK/m.
Among the above materials, steel has the least value of coefficient of conductivity. Therefore, steel is the bad conductor and the correct option is (b) steel.
Additional Information: Other than conduction, there are more than two types of processes for transfer of heat energy.
Convection – Mode of transfer of heat by means of migration of material particles of medium is called convection. In this process, unlike the conduction, the particles move from their equilibrium positions.
Radiation – The process of the transfer of heat from one place to another place without heating the intervening medium is called radiation. Here, it is the electromagnetic energy transfer in the form of electromagnetic waves through any medium.
Note: It is not that only a good conductor of heat is of importance. Bad conductors of heat also play a significant role in our lives. A simple example can be a frying pan. Although the flat round surface of the pan is a good conductor, it would not have been possible to hold the hot pan if it did not have a wooden handle. Wood is a bad conductor of heat