Question

The graph shows the variation of temperature (T) of one kilogram of a material with the heat (H) supplied to it, At O, the substance is in the solid state. From the graph, we can conclude that...

(A) T₂ is the melting point of the solid. 

(B) BC represents the change of state from solid to liquid. 

(C) (H₂ – H₁) represents the latent heat of fusion of the substance. 

(D) (H₃ – H₁) represents the latent heat of vaporization of the liquid.

Answer 1

The correct option is (C) (H₂ – H₁) represents the latent heat of fusion of the substance.

Explanation:

In region AB, temperature is constant 

∴ phase of material changes from solid to liquid & (H₂ – H₁) is the heat absorbed. This heat is heat of melting of solid. It is latent heat of fusion of the substance. 

In region CD, temperature is constant. 

∴ phase changes from liquid to gas and (H₄ – H₃) heat will be absorbed. This heat is heat of vaporization of liquid.