Question

During the change of state of a substance from solid to liquid, heat is absorbed by a body, but its temperature does not rise. Which of the following statements explains the phenomenon?

Options

• Only K.E of the molecules increases, but P.E remains the same.

• Only P.E of the molecules increases, but K.E remains the same.

• Both K.E and P.E of the molecules increase.

• There is no increase in the P.E and K.E of the molecules.

Answer 1

Only P.E of the molecules increases, but K.E remains the same.

Explanation:

During melting, the supplied heat is used to change the state of the substance. It increases the potential energy of the molecules by separating them further. The average kinetic energy does not increase, so the temperature stays constant.