(C)   $\frac{C-0}{100}=\frac{F-32}{180}$

         $C=\frac{5}{9}(F-32)\Rightarrow ∆C=\frac{5}{9}∆F$

         $40=\frac{5}{9}∆F\Rightarrow ∆F={72}^{o}F$

        $\therefore$ ${40}^o$ change on Celsius scale will corresponds to ${72}^o$ change on Fahrenheit scale.

(4)

$-10°C\text{ ice }\underset{\text{ change}}{\overset{\mathrm{Temp}.}{\to }}0°C\text{ ice}\underset{\text{ change}}{\overset{\mathrm{Temp}.}{\to }}0°C$

$\text{ water }\underset{\text{ change}}{\overset{\mathrm{Temp}.}{\to }}100°C\text{ water}\stackrel{\text{Phase change}}{\to }100°C\text{ steam}$

In this process, there are two phase changes and two temperature changes.

[IMAGE 109]