Thermal Capacity of a body is defined as the quantity of heat required to raise its temperature by unity.
Let the mass of a body be m and its specific heat is s. Heat gained by the body to raise its temperature by unity is H = m.s.1 = ms. By definition, this is the thermal capacity. It is usually denoted by the symbol C.
Hence, thermal capacity of a body = mass of the body x specific heat capacity of its material.
Units of Thermal Capacity:
The unit of Thermal Capacity in SI is J.K-1.
Relation between Thermal Capacity and Specific Heat:
We know that the thermal capacity of a body,
= mass of the body x specific heat of its material
specific heat of the material,
= thermal capacity of the body/mass of the body
If the mass of the body is 1, the specific heat of the material = thermal capacity of the body.
Hence, the thermal capacity of the unit mass of a body is the specific heat of its material.