Question

What will be the temperature change of 0.5 kg of water(c= 4200J/kg K) that loses 21000J.

Answer 1

$$Q=mc\Delta T,$$ $$\Delta T=\dfrac{Q}{mc},$$ \Delta T=\dfrac{21000\ J}{0.5\ kg\cdot4200\ \dfrac{J}{kg\cdot \!^{\circ}C}}=10^{\circ}C.