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
$Q_2=mL,L=$ 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.