Thermodynamics
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Question : 8
Total: 10
An electric heater supplies heat to a system at a rate of 100 W. If system performs work at a rate of 75 joules per second. At what rate is the internal energy increasing?
Solution:
Given that
Heat suppliedΔ Q = 100 W = 100 J s − 1
Useful work doneΔ W = 75 J s − 1
Change internal energyΔ U = ?
According to first law of thermodynamics, change in internal energy is given by
Δ U = Δ Q − Δ W
Δ U = 100 − 75
= 25 J s − 1 = 25 W
Heat supplied
Useful work done
Change internal energy
According to first law of thermodynamics, change in internal energy is given by
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