What is thermal expansion? Write only its types.

(N/A) Thermal expansion is the phenomenon where the dimensions of a body increase due to an increase in its temperature. When a substance is heated,its particles gain kinetic energy and vibrate more vigorously,leading to an increase in the average separation between them,which results in macroscopic expansion.
There are three types of thermal expansion:
$(a)$ Linear expansion: The expansion in the length of a solid is called linear expansion.
$(b)$ Area expansion: The expansion in the surface area of a solid is called area expansion.
$(c)$ Volume expansion: The expansion in the volume of a solid or fluid is called volume expansion.
These are illustrated as follows:
$(a)$ Linear expansion: $\frac{\Delta l}{l} = \alpha_l \Delta T$
$(b)$ Area expansion: $\frac{\Delta A}{A} = 2\alpha_l \Delta T$
$(c)$ Volume expansion: $\frac{\Delta V}{V} = 3\alpha_l \Delta T$