Question

Calculate the change in internal energy of the system if \(40\) kJ of work is done by the system, and it absorbs \(20\) kJ of heat

• A. \(-20\) kJ
• B. \(20\) kJ
• C. \(-60\) kJ
• D. \(40\) kJ

Hint:

Apply the first law with heat absorbed positive and work done by the system negative.

Answer 1

The Correct Option is A

Step 1: Energy Balance
The system gains 20 kJ as heat and loses 40 kJ as work.

Step 2: Net Change
Net change $= 20 - 40 = -20$ kJ.

Step 3: Result
This is option (A).

Final Answer:
The net change in internal energy is -20 kJ. \[ \boxed{\text{(A) }-20\ \text{kJ}} \]