Question

Choose the correct sequence of operations in the Carnot cycle.
A. Isothermal expansion of gas.
B. Isothermal compression of gas.
C. Adiabatic compression of gas.
D. Adiabatic expansion of gas.
Choose the correct answer from the options given below:

• A. A, B, C, D
• B. A, C, B, D
• C. B, A, D, C
• D. A, D, B, C

Hint:

Visualize the Carnot cycle on a P-V diagram. It starts at the top-left (high P, low V). The first stroke is a wide, shallow curve down (isothermal expansion, A). The next is a steep curve down (adiabatic expansion, D). The third is a short, shallow curve up (isothermal compression, B). The final is a steep curve up (adiabatic compression, C) to return to the start.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The Carnot cycle is a theoretical thermodynamic cycle that represents the most efficient possible cycle for converting heat into work or vice versa between two heat reservoirs. It consists of four reversible processes. The question asks for the correct order of these processes for a heat engine.
Step 2: Detailed Explanation:
The standard Carnot heat engine cycle proceeds as follows:
1. Reversible Isothermal Expansion: The gas expands at a constant high temperature \(T_H\), absorbing heat from the hot reservoir. This corresponds to step A.
2. Reversible Adiabatic Expansion: The gas continues to expand, but now adiabatically (no heat exchange). Its temperature drops from \(T_H\) to the low temperature \(T_C\). This corresponds to step D.
3. Reversible Isothermal Compression: The gas is compressed at a constant low temperature \(T_C\), rejecting heat to the cold reservoir. This corresponds to step B.
4. Reversible Adiabatic Compression: The gas is further compressed adiabatically, causing its temperature to rise from \(T_C\) back to the initial high temperature \(T_H\), completing the cycle. This corresponds to step C.
Step 3: Final Answer:
The correct sequence of operations for a Carnot cycle is Isothermal Expansion \(\rightarrow\) Adiabatic Expansion \(\rightarrow\) Isothermal Compression \(\rightarrow\) Adiabatic Compression. This corresponds to the sequence A, D, B, C.