A water heater of power 2000 W is used to heat water. The specific heat capacity of water is 4200 J kg^-1 K^-1. The efficiency of heater is 70 %.…

A water heater of power $\displaystyle 2000$ W is used to heat water. The specific heat capacity of water is $\displaystyle 4200$ J $\displaystyle \mathrm{kg}^{-1} \mathrm{~K}^{-1}$. The efficiency of heater is $\displaystyle 70 \%$. Time required to heat $\displaystyle 2$ kg of water from $\displaystyle 10^{\circ} \mathrm{C}$ to $\displaystyle 60^{\circ} \mathrm{C}$ is $\displaystyle \_\_\_\_$s. (Assume that the specific heat capacity of water remains constant over the temperature range of the water).