Latent heat is the heat required to convert a solid into a liquid or vapor phase, or a liquid into a vapor phase. According to the different phases, it has different names like the heat of condensation, the heat of vaporization, etc. The amount of heat energy absorbed or released for a phase change is known as latent heat.
Formula of Latent Heat
The latent heat formula is given by,
L = Q / M
Where,
Q = amount of heat
M = mass of the substance
Solved Examples
Example 1
Determine the latent heat of 5 kg substance if the amount of heat for a phase change is 300 k.cal.
Solution:
Given parameters are,
Q = 300 k.cal
M = 5 kg
The formula for latent heat is given by,
L = Q / M
L = 300 / 5
L = 60 k.cal/kg
Example 2
The heat needed for a phase transfer of 2 kg substance is 400k.cal. Determine its latent heat.
Solution:
Given parameters are,
Q = 400 k.cal
M = 2 kg
The formula for latent heat is given by,
L = Q / M
L = 400 / 2
LÂ = 200 k.cal/kg
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