Question

A gas absorbs 18 J of heat and work done on the gas is 12 J. Then the change in internal energy of the gas is:

• A. $24$ J
• B. $36$ J
• C. $6$ J
• D. $30$ J

Hint:

The internal energy change of a system is determined using the first law of thermodynamics, which considers heat and work interactions.

Answer 1

The Correct Option is D

Step 1: Apply First Law of Thermodynamics The first law of thermodynamics states: $$\Delta U = Q + W$$ where $Q$ is the heat absorbed by the system and $W$ is the work done on the system.
Step 2: Substitute Given Values Given $Q = 18$ J and $W = 12$ J: $$\Delta U = 18 + 12 = 30 \text{ J}$$