Specific Thermal Capacity of Material

When two bodies at different temperatures are kept in contact, heat is transferred from the hot body to the cold body till both of them acquire the same temperature. The two bodies then are called in thermal equilibrium. In acquiring thermal equilibrium the hot body loses heat and the cold body acquires an equal amount of heat.

Heat lost by hot body = Heat gained by cold body, provided we assure that there is no loss of heat to the surrounding.

If the temperature of hot body is more, the rise in the temperature of cold body will also be more i.e. heat transferred from a hot body to a cold body is directly proportional to their temperature difference,

Q ∝ Δθ

Similarly, if the mass of cold body is more it will absorb more heat from the hot body,

Q ∝ m

So,

Q ∝ mΔθ

Q = msΔθ

Where s is a constant of proportionality which depends on the nature of the material of the body. This is also called as the specific heat capacity of the material. The specific heat capacity of a material is defined as the amount of heat (in Joule) required to raise the temperature of 1 kg mass of that material through 1 K. The SI Unit of specific heat capacity (or simply specific heat) is J kg^–1 K^–1.

Of all substances water has highest value of specific heat.

Higher the value of specific heat of a substance lower will be the rate at which it is heated or cooled as compared to the substance of lower specific heat under identical conditions.