Almost all solids, liquids and gases expand on heating. The increase in the size of a body when it is heated is called thermal expansion.
Different type of thermal expansion:
It is the increase in the length of a metal rod on heating.
It is the increase in the surface area of a metal sheet on heating.
It is the increase in the volume of a block on heating.
If the substance is in the form of a long rod, then for a small change in temperature, ΔT, the fractional change in length, ∆l/l, is directly proportional to ΔT.
where α1 is known as the coefficient of linear expansion.
Similarly, we consider the fractional change in volume, ∆V/V, of a substance for temperature change ∆T and define the coefficient of volume expansion, αV as
Here αV is also a characteristic of the substance but is not strictly a constant. It depends in general on temperature (Fig). It is seen that αV becomes constant only at a high temperature.
We are sorry that this post was not useful for you!
Let us improve this post!
Tell us how we can improve this post? Please mention your Email so that we can contact you for better feedback.