An electric clothes dryer draws 20 A at 220 V. If the clothes put into the dryer have a mass of 7.0 kg when wet and 3.0 kg dry, how long does it take to dry the clothes? (Assume all heat energy goes into vaporizing water, L_v = 2.26 *10⁶ J/kg.)

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Quizplus · Accepted Answer

The power of the dryer is P = IV = 20 A * 220 V = 4400 W. The energy required to vaporize the water is Q = mL = (7.0 kg - 3.0 kg) * 2.26 * 10^6 J/kg = 9.04 * 10^6 J. The time required is t = Q/P = 9.04 * 10^6 J / 4400 W = 2054.55 s, which is approximately 34 minutes.

An Electric Clothes Dryer Draws 20 a at 220 V