Question

The SI unit of thermal capacity is:
A. \[Joule\]
B. \[Joule k{g^{ - 1}}\]
C. \[Joule k{g^{ - 1}} {K^{ - 1}}\]
D. \[Joule {K^{ - 1}}\]

Answer 1

Hint: We know that the thermal capacity is a physical property of matter, which is basically an amount of heat to be supplied to a mass of a material to increase a unit change in its temperature. It is also referred to as heat capacity also. It is denoted as $C$. In general words we can say that it is an amount of energy divided by a temperature change and its dimension is $\left[ {M{L^2}{T^{ - 2}}{\theta ^{ - 1}}} \right]$.

Complete answer:
heat required to raise the temperature of an object per unit mass of that object. Thermal heat is the extensive property means it varies with the amount of substance whereas specific heat capacity is an intensive property of matter. The heat capacity and the specific heat capacity are related as: $C = cm$, where $m$ is the mass of material, $c$ is the specific heat capacity.

Formula for the thermal capacity or heat capacity as follows: $C = \dfrac{Q}{{\Delta T}}$, where $\Delta T$ is the change in temperature and heat added is $Q$.

The unit for thermal capacity is joule per kelvin $J/K$ and for the specific heat capacity is joule per kelvin per gram $J/Kg$.

So, the correct answer is “Option D”.

Note:
Thermal capacity at the constant pressure contributes to the both the work done and the change in the internal energy. This is known as heat capacity at the constant process (isobaric process) ${C_P}$. At the constant volume (isochoric process) no work would be done so the heat supplied would participate only to the change in the internal energy. This is known as heat capacity at the constant volume ${C_V}$. The value of ${C_P}$ is always more than the value of ${C_V}$.