How long does it take for 1.5 liters of water in a 250 W electric kettle to heat up from 20 to 40 degrees?

univerkov | March 8, 2021 | education

Data: V (volume of water) = 1.5 l (1.5 * 10 ^ -3 m3); N (electric kettle power) = 250 W; t1 (initial temperature) = 20 ºС; t2 (final temperature) = 40 ºС.

Constants: ρw (density of water in the kettle) = 1000 kg / m3; С (specific heat) = 4200 J / (kg * ºС).

The time for heating the water in the kettle is determined from the formula: N = A / t = Q / t = C * m * (t2 – t1) / t = C * ρw * V * (t2 – t1) / t and t = C * ρw * V * (t2 – t1) / N.

Calculation: t = 4200 * 1000 * 1.5 * 10 ^ -3 * (40 – 20) / 250 = 504 s (8 min 24 s).

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