LEARNATHON
III

Competition for grade 6 to 10 students! Learn, solve tests and earn prizes!

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Theory:

Specific latent heat is defined as latent heat expressed per unit mass of a substance. It is denoted by the letter L.
If \(Q\) is the amount of heat energy absorbed or released by the ‘m' mass of a substance during its phase change at a constant temperature, then the specific latent heat is given by
 
L=Qm
 
As a result, specific latent heat is the amount of heat energy absorbed or liberated by a unit mass without causing a temperature change during a state change. J/kg is the SI unit for specific latent heat.
 
Let us look at the example problem.
 
1. How much heat energy is required to melt 4 kg of ice? (Specific latent heat of ice = 336 J/g)
  
Given:
 
Mass (\(m\)) \(=\) \(4 kg\)
 
Specific latent heat of ice (\(L\)) \(=\) \(336 J/g\)
 
To find: Heat energy (\(Q\))
 
L=QmByrearranging,theformulabecomesQ=L×mQ=336×4000Q=1344000orQ=1.3×106J