An electric clothes dryer draws 15 A at 220 V.If the clothes put into the dryer have a mass of 7.0 kg when wet and 4.0 kg dry,how long does it take to dry the clothes? (Assume all heat energy goes into vaporizing water,L_v = 2.26 x 10⁶ J/kg).

Question

Quizplus · Accepted Answer

First, we need to find the amount of energy required to vaporize the water in the wet clothes.

Mass of water in wet clothes = 7.0 kg - 4.0 kg = 3.0 kg

Energy required to vaporize 1 kg of water = Lf = 2.26 x 10^6 J/kg

Energy required to vaporize 3.0 kg of water = 3.0 kg x 2.26 x 10^6 J/kg = 6.78 x 10^6 J

Now, we can use the formula:

Energy = Power x Time

Where power = voltage x current

So, 6.78 x 10^6 J = (220 V x 15 A) x time

Solving for time, we get:

time = 6.78 x 10^6 J / (220 V x 15 A)

time = 34 minutes

Therefore, the answer is B) 34 min.

An Electric Clothes Dryer Draws 15 a at 220 V