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Latent Heat: The Hidden Heat in Phase Changes Explained

Latent heat is the energy required to change the state of a substance without changing its temperature. When water boils, it absorbs latent heat of vaporiz

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TL;DR: Latent heat is the energy required to change the state of a substance without changing its temperature. When water boils, it absorbs latent heat of va…

Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated Jul 23, 2026

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Latent Heat: The Hidden Heat in Phase Changes: Latent heat is the energy required to change the state of a substance without changing its temperature. When water boils, it absorbs latent heat of vaporiz

Latent Heat: The Hidden Heat in Phase Changes Explained Simply

Latent heat is the energy required to change the state of a substance without changing its temperature. When water boils, it absorbs latent heat of vaporiz This is a key physics concept for 10.

Frequently Asked Questions

Why does water take so long to boil?

Boiling requires latent heat of vaporization, which is very large (2.26 million joules per kilogram). All this energy goes into breaking bonds between water molecules and converting liquid to gas at constant 100°C temperature.

Why do ice cubes eventually melt in a freezer even though it is cold?

Ice slowly evaporates (sublimes) even below 0°C by absorbing latent heat from the freezer. This is called frost formation. If a freezer is cold enough (below -20°C) and air is dry, ice persists longer because sublimation is slower.

How do evaporative coolers cool air without consuming electricity for compression like air conditioners?

They use latent heat of vaporization. Water evaporating absorbs massive amounts of latent heat directly from air, cooling it by 10-15°C. Only a fan is needed to circulate air through wet pads, consuming much less power than refrigerants compressors.

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