Question
Water is boiled at 1 × 105 Pa 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 18 minutes. If the heat loss from the coffee maker is negligible, the power rating of the heating element is
The correct answer is
1.05 kW
At approximately 1 bar, use latent heat 2257 kJ/kg. Once boiling has begun, \(P=mh_{fg}/t=0.5(2257)/(18\times60)=1.0449\ \mathrm{kW}\). The closest option is 1.05 kW.
Was this answer helpful?
Important Questions from Fourier Law and Thermal Conductivity
Which of the following substances has the minimum value of thermal conductivity ?
- The rate of flow of heat through a simple homogeneous solid is directly proportional to the area of the section at right angles to the direction of heat flow, and _______.
The SI unit of Thermal Conductivity is
Which of the following has max. value of thermal conductivity?
- A steam pipe is to be insulated by two insulating materials put over each other. For best result
Need Expert Advice?
