What is compressibility? Give its unit and dimensional formula.

(A) Compressibility is defined as the reciprocal of the bulk modulus $(B)$. It represents the fractional change in volume per unit increase in pressure.
The formula for compressibility $(k)$ is:
$k = \frac{1}{B} = -\frac{1}{V} \left( \frac{\Delta V}{\Delta p} \right)$
Unit:
The $SI$ unit of compressibility is $Pa^{-1}$ or $m^2/N$.
Dimensional Formula:
Since $B = \frac{\text{Force}}{\text{Area}} \times \frac{\text{Volume}}{\text{Change in Volume}}$,the dimensions of $B$ are $[M L^{-1} T^{-2}]$.
Therefore,the dimensional formula for compressibility is $[M^{-1} L^1 T^2]$.