A kettle has a 55% energy efficiency. The input energy for the kettle is 378,000 J per boil. Calculate the amount of energy dissipated in 5 boils.

Energy used for one boil = (3.78 x 105 / 100) x 55Energy used for one boil = 2.079 x 105 J Energy lost per boil = 3.78 x 105 -2.079 x 105Energy lost per boil = 1.701 x 105Energy lost per 5 boils = (1.701 x 105) x 5Energy lost per 5 boils = 8.51 x 105 J, 3 s.f. (or 851 kJ)

Answered by Ryan A. Physics tutor

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