Physics - Heat & Thermo Question with Solution | TestHub

A 1.0 kW heater warms 0.50 kg water from 20°C to 100°C and then boils it all away. Only 80\% of input power reaches the water. Use $c_w=4000\mathrm{J}{\mathrm{kg}}^{-1}{\mathrm{K}}^{-1}$ and $L_v=2.0\times 10^6\mathrm{J}{\mathrm{kg}}^{-1}$. Find total time in seconds.