Question

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: If dQ and dW represent the heat supplied to the system and the work done on the system respectively. Then according to the first law of thermodynamics $dQ = dU – dW$.
Reason R: First law of thermodynamics is based on law of conservation of energy.
In the light of the above statements, choose the correct answer from the options given below :

• A. Both A and R are correct and R is the correct explanation of A
• B. A is correct but R is not correct
• C. A is not correct but R is correct
• D. Both A and R are correct but R is not the correct explanation of A

Answer 1

Answer: (A)

Both A and R are correct and R is the correct explanation of A

Answer 2

∆Q = heat supplied to system
∆W = work done on the system
∴ ∆U = ∆Q – ∆W
This comes from conservation of energy.