An electric immersion heater of 1.08 kW is immersed in water. After the water has reached a temperature of 100℃ , how much time will be required to produce 100 g of steam

The heat required for producing  1 g of steam =540×4.2 J=2268 J. Energy given by immersion heater is =1.08 kW=1080W. Now time taken to produce 100g of steam =(2268×100)/1080=210 sec