Question

A block of ice at $-10^{\circ} C$ is slowly heated and converted to steam at $100^{\circ} C$. Which of the following curves represents the phenomena qualitatively?

• A.
• B.
• C.
• D.

Answer 1

Answer: (A)

The temperature of ice will first increase from $-10^{\circ} C$ to $0^{\circ} C$.
Heat supplied in this process will be
$Q_{1} =m s_{i}(10)$
where, $ m =$ mass of ice
$s_{i} =$ specific heat of ice

Then, ice starts melting. Temperature during melting will remain constant $\left(0^{\circ} C \right)$.
Heat supplied in this process will be
$Q_{2}=m L, L=$ latent heat of melting.
Now the temperature of water will increase from $0^{\circ} C$ to $100^{\circ} C$. Heat supplied will be
$Q_{3}=m s_{w}(100)$
where, $ s_{w}=$ Specific heat of water.
Finally, water at $100^{\circ} C$ will be converted into steam at $100^{\circ} C$ and during this process temperature again remains constant. Temperature versus heat supplied graph will be as shown in above figure.