A source supplies heat to a system at the rate of 1000   W . If the system performs work at a rate of…

A source supplies heat to a system at the rate of 1000 W. If the system performs work at a rate of 200 W. The rate at which internal energy of the system increases is

  1. 600 W
  2. 800 W
  3. 500 W
  4. 1200 W

Solution

According to the first law of thermodynamics, Q=W+U.

Upon differentiation, we get 

dQdt=dWdt+dUdtdUdt=dQdt-dWdt

Given: dQdt=1000 W

dWdt=200 W

Therefore, dUdt=1000 W-200 W=800 W

Asked in: JEE Main 2023 (06 Apr Shift 1)

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