Question

How much heat does a body lose when $0.36$g of sweat evaporated from the skin at ${25}^0$C? (Assume that sweat contains only water).

Answer 1

$Q=mS\Delta t$

Given $m=0.36g=0.36\times {10}^{-3}kgs$

$S=4200J/kgK$

$\Delta t={25}^{o}C={25}^{o}K$

Because, number of divisions in centigrade scale and Kelvin scale are equal.

So, $Q=0.36\times {10}^{-3}\times 4200\times 25$

$=37.8J$

Heat energy is $37.87$ .