Question

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: If $d Q$ and $d W$ represent the heat supplied to the system and the work done on the system respectively. Then according to the first law of thermodynamics $d Q=d U-d W$.
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 but $R$ is not 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 and $R$ is the correct explanation of $A$

Answer 1

Answer: (D)

First law of thermodynamics is based on law of conservation of energy and it can be written as $dQ = dU - dW$.
where $dW$ is work done on the system