Volume $=(\text { side })^3$
$v=(a)^3$
So $\frac{\Delta V}{V}=\frac{3 \Delta a}{a}$ $\left\{\operatorname{given} \frac{\Delta a}{a}=-2 \%\right\}$
$\therefore \frac{\Delta v}{v}=3 \times-2 \quad \text { Side decreases solve used (-)ve sign }$
$=-6 \%$
We know
$\frac{\Delta v}{v}=-\frac{P}{B}$
Substituting value of $\Delta v / v$
$-\frac{6}{100}=-\frac{P}{B}$
So bulk strain produced is $0.06$
