A block of ice at `-10^@C` is slowly heated and converted to steam at `100^@C.` Which of the following curves represents the phenomenon qualitatively?

Options

A.
B.
C.
D.

Answer

A

Explanation

When heat is supplied the temperature of ice increase from `-10^(@)C " to " 0^(@)C`. It is represented by a straight line inclined to heat axis. At `0^(@)C` the heat is used in converting ice into water at `0^(@)C`. This stage is represented by horizontal straight portion. After that temperature of water risesfrom `0^(@)C` to `100^(@)C`. It is represented by a straight line inclined to heat axis. At `100^(@)C`, the heat is used in converting water into steam. The graph is represented by horizontal straight line. Thus option (a) is correct.