(a) If coefficient of volume expansion is $\alpha$ and rise in temperature is $\mathrm{\Delta}\theta$ then $\mathrm{\Delta}V = V\alpha\mathrm{\Delta}\theta \Rightarrow \frac{\mathrm{\Delta}V}{V} = \alpha\mathrm{\Delta}\theta$
Volume elasticity $\beta = \frac{P}{\mathrm{\Delta}V/V} = \frac{P}{\alpha\mathrm{\Delta}\theta} \Rightarrow \mathrm{\Delta}\theta = \frac{P}{\alpha\beta}$