Time to boil 100Litres of water with 1000 watts

It takes about 2260 joules to bring 1mL of water to boiling. Accordingly, it will take 2260*10^5 joules to bring 100L of water to boiling. Since we have only 1000 watts and we know of t=E/P, we get t=226000sec.

we need to know the temprature of the water , and then we can use the following equation

Q= m cp (T1-T1) = jouls , so lets say the first tempratue is 25 dec and the water boiling is 100 dec , cp = 4.18 joul/kg.dec

so 100 liters of water = 100 kg , density = 1000 kg/m3

  m = density * vol = 1000 kg/m3 * 0.1 m3 = 100 kg

so q= 100 * 4.18 * (100-25) = 31350 kjoul

the power = work /time => 1000 watt = 31350 *1000 /t => t = 31350 second

= 522.5 mins = 8.7 hours to boil the water