What is latent heat?
If the amount of latent heat required to change the state of a substance of mass ‘m’ is ‘Q’ then the latent heat formula is;
The latent heat of fusion of water is;
After the ice has all melted, the temperature of the water begins to rise again till it reaches 1000C. If Ice is the lowest energy state of water, gas is the other extreme; gas molecules have the most energy and are constantly whizzing around. This energy to whizz around comes from the heat we supply to it. Remember that water exists as a liquid due to intermolecular forces of attraction which needs to be overcome in order to turn it into gas.
The latent heat of vaporization of water is;
Latent Heat of Vaporization is 7.5 times as large as the Latent Heat of fusion i.e. the energy required to melt something is considerably lower than the energy required to vaporize something. This is the reason why a burn caused by steam at 1000C will be a lot more severe than a burn caused by water at 1000C. The graph below shows the two state changes of water and their corresponding temperature changes.
Practise This Question
|CBSE Physics Syllabus Class 6||CBSE Physics Syllabus Class 7||CBSE Physics Syllabus Class 8||CBSE Physics Syllabus Class 9||CBSE Physics Syllabus Class 10|