An electric kettle takes 4 A current at 220 V. How much time will it take to boil 1 kg of water from temperature 200C? The temperature of boiling water is 1000C

Heat evolved due to Joule's effect is used up in boiling water.VIt = ms∆t   or t = ms∆tVIWe are given I = 4 A, V = 200 volt, m = 1 kg∆t = (100-20)0C, s = 4200 J/kg0Ct = 1×4200×80220×4 = 6.3 min