Water flows through an electric shower at a rate of 6kg per minute. Assuming no heat is transferred to the surroundings, what power is required to heat the water by 20K as it flow through the shower?
To find the necessary power, we need to know how much water is flowing every second, and how much energy we need to heat that amount of water.
Amount of water = 6kg per minute = 6/60 kg per second = 0.01 kg per second
energy to heat 0.01kg of water: Q = mCΔT = 0.01 x 4200 x 20= 840J
and so to do that every second the shower needs 840W of power.
TB
Related Physics A Level answers
All answers ▸What is the difference between plastic and elastic collision?
A small ball of mass 150 g is placed at a height of 20cm above the ground on an incline of 35°. It is released and allowed to roll down the slope; what will be the ball's speed when it reaches the ground? Assume friction and air resistance can be ignored.
Assuming the Earth is a perfect sphere of radius R. By how much would your mass (m), as given by a scale, change if you measured it on the north pole and on the equator?
Explain what is meant by the mass defect of an atomic nucleui