Question

Which of the following process is possible according to the first law of thermodynamics?

• A. \( W > 0, Q < 0, \Delta U = 0 \)
• B. \( W > 0, Q < 0, \Delta U > 0 \)
• C. \( W > 0, Q > 0, \Delta U < 0 \)
• D. \( W < 0, Q > 0, \Delta U < 0 \)

Hint:

In thermodynamics, the first law relates the change in internal energy to the heat and work done.

Answer 1

The Correct Option is C

Step 1: First law of thermodynamics.
The first law of thermodynamics is expressed as: \[ \Delta U = Q - W \] where \( \Delta U \) is the change in internal energy, \( Q \) is the heat added to the system, and \( W \) is the work done by the system.

Step 2: Analyzing the options.
Option (3) satisfies the first law where heat is added (\( Q > 0 \)) and work is done by the system (\( W > 0 \)), with a decrease in internal energy (\( \Delta U > 0 \)). Thus, the correct answer is (3).