How to I solve this.. heat water..?

Question

How many minutes would be required for a 300 W immersion heater to heat 250 g of water from 20 degrees C to 100 degrees C?

Answer 1

specific heat 4.186 kJ/kgC

energy required is

E = 4.186 kJ/kgC x 0.25kg x 80C = 83.7 kJ

300 watts is 300 J/s

83700 J / 300 J/s = 279 seconds or 4.7 minutes

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