Question:medium

A Carnot engine operates between temperatures of $ 600 \, \text{K} $ and $ 300 \, \text{K} $. If it absorbs $ 900 \, \text{J} $ of heat from the source, how much work does it perform?

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Carnot engine is the most efficient heat engine. Use: \[ \eta = 1 - \frac{T_C}{T_H}, \quad W = \eta Q_H \] where temperatures are in kelvin.
Updated On: Jan 13, 2026
  • 300 J
  • 450 J
  • 600 J
  • 150 J
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The Correct Option is A

Solution and Explanation

A Carnot engine functions between a hot reservoir at \( T_H = 600 \, \text{K} \) and a cold reservoir at \( T_C = 300 \, \text{K} \). It takes in \( Q_H = 900 \, \text{J} \) of heat from the hot reservoir. The objective is to calculate the work \( W \) output by the engine.

The efficiency \( \eta \) for a Carnot engine is defined by the equation:

\(\eta = 1 - \frac{T_C}{T_H}\)

Plugging in the provided temperatures yields:

\(\eta = 1 - \frac{300}{600} = 1 - 0.5 = 0.5\)

The efficiency can also be represented as the ratio of work done to heat absorbed:

\(\eta = \frac{W}{Q_H}\)

Solving for work \( W \):

\(W = \eta \times Q_H\)

Substituting the known values:

\(W = 0.5 \times 900 \, \text{J} = 450 \, \text{J}\)

Consequently, the work performed by the Carnot engine is 450 J, aligning with the second option previously indicated.

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