question_answer

A block of ice at temperature \[-20{}^\circ C\] is slowly heated and converted to steam at \[100{}^\circ C\]. Which of the following diagram is most appropriate?

A)     

B)

C)  

D)

Correct Answer: A

Solution :

[a]: When heat is supplied, the temperature of ice increases from \[-20{}^\circ C\]to \[0{}^\circ C\]. It is represented by a straight line inclined to heat axis. At \[0{}^\circ C\], the heat is used in converting ice into water. It is represented by horizontal straight portion. After that, heat is supplied to increase the temperature of water from \[0{}^\circ C\] to \[100{}^\circ C\]. It is represented by a straight line incline to heat axis. At \[100{}^\circ C\], the heat is used in converting water into steam. It is represented by horizontal straight line. Hence option [a] is correct.