The graph given below indicates change in temperature (0) when heat (Q) was given to a substance. Which among the following parts of the graph correctly depict the latent heat of the substance?

A heating curve illustrates the relationship between heat added and temperature change for a substance. In such graphs, sloped segments (like AB, CD, and EF) represent phases where heat addition increases the average kinetic energy, thereby raising the temperature [2]. Conversely, horizontal plateaus represent phase changes where the temperature remains constant despite continuous heat addition [1]. This constant-temperature heat is known as latent heat, which is used to break intermolecular forces rather than increasing temperature [2]. Specifically, the first plateau (BC) represents the latent heat of fusion as the substance melts from solid to liquid, and the second plateau (DE) represents the latent heat of vaporization as the liquid transitions into a gas [1]. Therefore, segments BC and DE correctly depict the latent heat of the substance.

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 22: Vertical Distribution of Temperature > Explanation > p. 295
2. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 22: Vertical Distribution of Temperature > Latent Heat > p. 294