Latent Heat — Prelims Questions

How much heat energy is required to convert $100,\text{g}$ of ice at $0^circ\text{C}$ to water at $20^circ\text{C}$? (Given: Latent heat of fusion of ice = $3.34 \times 10^5,\text{J/kg}$, Specific heat capacity of water = $4186,\text{J/kg}^circ\text{C}$)

Which of the following statements about latent heat is INCORRECT?

A $5,\text{kg}$ block of a substance is heated. Its temperature-versus-heat-supplied graph is shown. If the substance melts at $100^circ\text{C}$, what is its latent heat of fusion? (Assume the graph shows a plateau at $100^circ\text{C}$ from $100,\text{kJ}$ to $300,\text{kJ}$ of heat supplied).

Steam at $100^circ\text{C}$ causes more severe burns than water at $100^circ\text{C}$ because:

A refrigerator removes $200,\text{J}$ of heat from its contents for every $1,\text{g}$ of refrigerant that evaporates. If the latent heat of vaporization of the refrigerant is $100,\text{J/g}$, what is the efficiency of the refrigerator in terms of heat removal per gram of refrigerant?

Which of the following processes involves the release of latent heat?