The heat energy released by water of mass $2 \,kg$ when it is cooled by $10^{\circ} C$ is (Specific heat capacity of water $= 4200 \,J \,kg^{-1} \,K^{-1}$) (in $\,J$)

Water of mass $5 \ kg$ in a closed vessel is at a temperature of $20^{\circ} C$. If the temperature of the water when heated for a time of $10 \ minutes$ becomes $30^{\circ} C$, then the increase in the internal energy of the water is (Specific heat capacity of water $= 4200 \ J \ kg^{-1} \ K^{-1}$) (in $kJ$)

What is the heat capacity of a substance?

Water is used to cool radiators of engines,because

Derive the equation for the molar specific heat capacity of solids.

If some heat is given to a metal of mass $100 \ g$,its temperature rises by $20^{\circ} C$. If the same heat is given to $20 \ g$ of water,the change in its temperature (in $^{\circ} C$) is (The ratio of specific heat capacities of metal and water is $1: 10$).