Consider a water heater meant to increase the temperature from 25 C to 100 C.

Consider a water heater meant to increase the temperature from 25 ^οC to 100 ^οC. A manufacturer advertises the heater as 80 percent efficient. This is the first law efficiency, which means that 20 percent of the energy input is lost. 

1. Calculate the energy input needed to heat a kilogram of water. 

2. Determine the least amount of energy required for heating this water, and the second law efficiency of the current device.