Question

Water is boiled at 1 atm pressure in a coffee maker equipped with an immersion-type electric heating element. The coffee maker initially contains 1 kg of water. Once boiling started, it is observed that half of the water in the coffee maker evaporated in 12 min. If the heat loss from the coffee maker is negligible, what is the power rating of the heating element?

Answer 1

1.57 KW

Step-by-step explanation:

given data:

P= 1 atm

T= 12 min

power rating=??

solution:

latent heat of vaporization (L) of water at 1 atm = 2257.5 KJ/Kg

half of the water is evaporated in 12 min

so power rating is,

=P×L/2.T

=1×2257.5 /2×12×60

=1.57 KW