Calculate the time required to heat `20kg` of water from `10^(@)C to 35^(@)C ` using an immersion heater `1000W` Assume that `80%` of the power input is used to heat the water. Specific heat capacity of water `= 4200J kg^(-1)K^(-1)`

Answer

D

Explanation

Total heat required to raine the temperature of `20kg` of water from `10^(@)C to 35^(@)C`
`= 20 xx 4200 xx 25`
` = 20 xx 4200 xx 25 = 21 xx 10^(6)J`
Energy utilized ` = t xx (0.080) xx 1000`
Equation now, we get
`t = (21 xx 10^(5))/(800) = 44 min`