calculate the time taken to raise the temperature of 1.5 kg of water in a kettle from 15°C to 100°C given that specific heat capacity of water is 4200 J/kg/K and the heater is rated 250V , 2kW

270 s or 4.5 min

Explanation:

First find the amount of heat needed:

q = mCΔT

q = (1.5 kg) (4200 J/kg/K) (100 − 15) K

q = 535,500 J

q = 535.5 kJ

Power is energy per time.

P = E / t

2 kW = 535.5 kJ / t

t = 270 s

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