RRB Technician Grade 1 Model Paper 5

Concept:Latent heat of steam refers to the heat required to convert $1$ gram of boiling water at $100^\circ\text{C}$ into steam without changing its temperature.Explanation:During a change of state, heat absorbed or released does not change the temperature of the substance. This heat is called latent heat.For water converting to steam at its boiling point, the latent heat of vaporisation is fixed.The latent heat of steam is given as:$$L = 540\ \text{cal/gram}$$This value is larger than the latent heat of fusion of ice, which is $80\ \text{cal/gram}$.Thus, the correct value for latent heat of steam is $540\ \text{cal/gram}$.Answer:B. $540$ cal/gram