All Exams Test series for 1 year @ ₹349 only
Question

______ is the heat per unit mass required to change a substance from solid into liquid at the same temperature and pressure.

This question was previously asked in
RRB ALP/Technician 2018 CBT 2 Electronics Mechanic Question Paper (23-Jan-2019) (Shift 1)
The correct answer is
Latent heat of fusion

Latent Heat of Fusion Definition

The heat required per unit mass to change a substance from a solid state to a liquid state, without altering its temperature or pressure, is defined as the latent heat of fusion.

This energy is necessary to break the bonds that hold the molecules in a fixed position within the solid lattice.

The specific latent heat of fusion (\(L_f\)) is calculated using the formula:

\(L_f = \frac{Q}{m}\)

where \(Q\) is the heat absorbed and \(m\) is the mass of the substance undergoing the phase change.

Distinguishing Fusion from Other Processes

It is crucial to differentiate latent heat of fusion from other related terms:

  • Regelation: This is a phenomenon where ice melts under pressure and refreezes when the pressure is reduced. It relates to the effect of pressure on the melting point.
  • Sublimation: This is the transition directly from solid to gas, bypassing the liquid phase.
  • Vaporisation: This is the phase transition from liquid to gas.

Only the latent heat of fusion specifically addresses the energy needed for the solid-to-liquid transition at constant temperature and pressure.

Was this answer helpful?

Similar Questions

  1. Which of the following options does NOT represent a property of solids?

  2. Which of the following statements is correct about continuous movement of particles of matter?

  3. When 1 kg of water is cooled from \(4^\circ\text{C}\) to \(0^\circ\text{C}\), its volume ______.
  4. Density of ice is ______ compared to density of water.
  5. Which of the following glows with special colour depending on the nature of gas in the fluorescent tube?
  6. Which of the following statement is INCORRECT ?

  7. Which of the following does not increase the rate of evaporation ?

  8. Which of the following options does not represent a property of suspension?

  9. Which of the following non - metals is a liquid ?

  10. Which of the following is an example of heterogeneous solution?


Important Questions from States of Matter

  1. Which is correct statement ?

  2. According to Charle's Law, which of the following is constant?

  3. Which of the following statements is/are correct?

    I. Mass vapor is obtained in the air by evaporation and transpiration.

    II. Water circulation between the oceans and the water bodies is called the water cycle.

  4. Which gas gives pungent smell to LPG cylinders as a warning of leakage?

  5. If C Sand C Iare the equilibrium concentration of impurities in the solid and liquid near the interface respectively, then for dilute solutions encountered in silicon growth, an equilibrium segregation coefficient k amay be defined as:

Need Expert Advice?
Upcoming Exams
RRB ALP
November 03, 2026
Test Series
RRB ALP img
Railways
RRB ALP 2026 Mock Test series
1035 Tests 1 Tests Free
1669 Attempts
4.3(257)
English, Hindi

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App