question_answer

This question has Statement 1 and Statement 2.

Of the four choices given after the Statements, choose the one that best describes the two Statements.

Statement 1: An inventor claims to have constructed an engine that has an efficiency of 30% when operated between the boiling and freezing points of water. This is not possible.

Statement 2: The efficiency of a real engine is always less than the efficiency of a Carnot engine operating between the same two temperatures.                                                                         [JEE ONLINE 19-05-2012]

A)        Statement 1 is true, Statement 2 is true, and Statement 2 is not the correct explanation of Statement 1.

B)       Statement 1 is true. Statement 2 is false.

C)    Statement 1 is false, Statement 2 is true.

D)       Statement 1 is true. Statement 2 is true, Statement 2 is the correct explanation of Statement 1.

Correct Answer: D

Solution :

[d] According to Carnot's theorem - no heat engine working between two given temperatures of source and sink can be more efficient than a perfectly reversible engine i.e. Carnot engine working between the same two temperatures.

Efficiency of Carnot's engine, where, temperature of source  temperature of sink