Carnot Cycle

Step 1: In the given P-V diagram:
• AB is an isobaric process.
• BC is an isothermal/curved path
• CD is an isochoric process
• DA is an isothermal/curved path

Step 2: When the same cycle is represented in a P-T diagram:
• Isobaric processes appear as horizontal lines
• Isochoric processes appear as straight lines through origin
• Isothermal processes appear as vertical lines

Step 3: Comparing these characteristics with the given options, only diagram (b) correctly preserves the nature and sequence of processes.

A Carnot engine operates between two temperatures: the hot reservoir at and the cold reservoir at . It absorbs of heat from the hot reservoir. We need to find the work performed by the engine.

The efficiency of a Carnot engine is given by the formula:

Substitute the given temperatures into the efficiency equation:

The efficiency can also be expressed in terms of work done and heat absorbed as:

Rearranging for work , we get:

Substitute the known values:

Therefore, the work performed by the Carnot engine is 450 J, which corresponds to the second option noted earlier.