Question

Heat is absorbed by a body, but its temperature does not increase. Which of the following statement explains the phenomena?

• A. Only K.E. of vibration increases
• B. Only P.E. of inter molecular force changes
• C. No increase in internal energy takes place
• D. Increase in K.E. is balanced by decrease in P.E.

Answer 1

The correct option is B Only P.E. of inter molecular force changes

The heat energy necessary to bring about the change of state that does not appear externally is called the latent heat.

During the change of state, the energy supplied (latent heat) breaks up the inter-molecular interactions and only the potential energy stored of these inter-molecular force changes. So, the temperature remains constant until all the interactions are completely disrupted.

For example during the change of state from ice to water heat is absorbed but the temperature does not rise.