Explanation

(a) The temperature of ice will increases from $- 10℃\ to\ 0℃$ .
Heat supplied in this process will be
$Q = ms_{i}(10)$
Here, $m$=mass of ice
$s_{i}$=specific heat of ice
Then ice starts melting. Temperature during melting will remain constant (0$℃)$. Heat supplied in this process will be
$Q_{2} = mL\ where,\ L = latent\ heat\ of\ melting$
Now, the temperature of water will increase from $0℃\ to\ 100℃$ . Heat supplied will be $\mathcal{Q}_{3} = ms_{w}(100)$
where $s_{w} = specific\ heat\ of\ water$.
Finally water at 100$℃$ will be converted into steam at 100$℃$ and during this process temperature again remains constant. Temperature $versus$ heat supplied graph will be as follows