Key concept According to principle of calorimetry states that total heat given by a hotter body is equal to the total heat received by colder body
i.e. heat lost by hotter body = heat gained by colder body
Heat required to melt 1g of ice at 0∘C into 1g of water at 0∘C is 80cal.
Heat required to convert 1g of water at 0∘C into 1g of water at 100∘C=1×1×100=100cal
Heat required to condense 1g of steam =1×540cal=540cal
Clearly, whole of steam is not condensed. So, temperature of the mixture is 100∘C.