ExamBro
ExamBro
NEET · Physics · STD 11 - 11. thermodynamics

An electric heater supplies heat to a system at a rate of 100 W. If the system performs work at a rate of 75 J/s, then the rate at which internal energy increases will be :

  1. A 75 W
  2. B 100 W
  3. C 125 W
  4. D 25 W
Verified Solution

Answer & Solution

Correct Answer

(D) 25 W

Step-by-step Solution

Detailed explanation

(D) 25 W
According to the first law of thermodynamics:
\(\frac{d Q}{d t}=\frac{d U}{d t}+\frac{d W}{d t}\)
Given that the rate of heat supplied is \(\frac{d Q}{d t}=100 W\) and the rate of work done by the system is \(\frac{d W}{d t}=75 J / s =75\) W.
Substituting the values:
\(100=\frac{d U}{d t}+75\)
\(\frac{d U}{d t}=100-75=25 W\)
The rate at which internal energy increases is 25 W .
Same subject
Explore more questions on app
From NEET
Explore more questions on app