Share
An electric heater supplies 5kw of power to atank of water assume all the energy supplied is converted into heat energy and the energy losse
Question
An electric heater supplies 5kw of power to atank of water assume all the energy supplied is converted into heat energy and the energy losses to the surrounding are negligible how long will it take to heat 500 kg of water in the tank from 25c to 100c specifiv heat capacity water 4200j/kgc
in progress
0
Physics
5 years
2021-08-06T19:52:14+00:00
2021-08-06T19:52:14+00:00 1 Answers
72 views
2
Answers ( )
Answer:
8hours 45minutes
Explanation:
Amount of heat energy used up by the electric substance = heat gained by the water.
Amount of heat energy used up by the electric substance = Power * Time
heat gained by the water. = mcΔt
m is the mass of the water in kg
c is the specific heat capacity
Δt is the change in temperature
Given parameters
Power = 5kW = 5000W
mass of water m = 500kg
c = 4200J/kgC
Δt = 100°C – 25°C = 75°C
Required
Time taken
Substituting the given parameters into the formula
Pt = mcΔt
5000t = 500*4200*75
5000t = 157,500,000
Divide both sides by 5000
t = 157,500,000/5000
t = 31,500 secs
t = (31,500/3600)hrs
t = 8.75hours
t = 8hours 45minutes
Hence it takes 8hours 45minutes to heat 500 kg of water in the tank from 25c to 100c