Explanation

(a) $\frac{h_{1}}{h_{2}} = \frac{\rho_{2}}{\rho_{1}} = \frac{(1 + \gamma\theta_{1})}{(1 + \gamma\theta_{2})}\ \ \ \ \ \ \ \left\lbrack \because\rho = \frac{\rho_{0}}{(1 + \gamma\theta)} \right\rbrack$
$\Rightarrow \frac{50}{60} = \frac{1 + \gamma \times 50}{1 + \gamma \times 100} \Rightarrow \gamma = 0.005/℃$