Q. 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) $T_{2}$ is the melting point of the solid
B) $BC$ represents the change of state from solid to liquid
C) $(H_{2} - H_{1})$ represents the latent heat of fusion of the substance
D) $(H_{3} - H_{1})$ represents the latent heat of vaporization of the liquid
Explanation
(c) Since in the region $B$ temperature is constant therefore at this temperature phase of the material changes from solid to liquid and $(H_{2} - H_{1})$ heat will be absorb by the material. This heat is known as the heat of melting of the solid.
Similarly in the region $CD$ temperature is constant therefore at this temperature phase of the material changes from liquid to gas and $(H_{4} - H_{3})$ heat will be absorbed by the material. This heat as known as the heat of vaporisation of the liquid
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.