Question

Define the coefficient of volume expansion.

Answer 1

1. When a solid is in bulk form that is in the form of a cube, cuboid, or sphere, etc. then on heating, its volume increases, this is called volume expansion.
2. It is observed that if the change in volume of the solid is $∆\mathrm{V}$ then $∆\mathrm{V}$ proportional to the product of the original volume($V$) and the change in temperature($∆\mathrm{T}$).
3. Thus, it can be written as;

$$\begin{gathered} ∆V\propto V\times ∆T \\ ∆V=\gamma V\times ∆T \\ Here,\gamma isthecoefficientofvolumeexpansionofthegivensolidmaterial. \\ fromhere, \\ \gamma =\frac{∆V}{V\times ∆T} \end{gathered}$$

From the above relation,

1. The coefficient of volume expansion of the material of bulk solid is defined as the increase in its volume per unit of original volume per degree rise in temperature.
2. Its SI unit is K^-1 but it is commonly expressed in ⁰C^-1 (per degree Celsius).