Question

The thermal efficiency of a heat engine for which the work output is $2500J/cycle$ and the heat input is $10000J/cycle$, is:

• A. $75$
• B. $40$
• C. $25$
• D. $0.25$

Answer 1

Answer: (D)

$0.25$

$\text{Given:-}$ The work output of the engine is,$W=2500J/cycle$

The heat input to the engine is, $Q=10000J/cycle$

$\text{Solution:-}$

Express the relation for the efficiency of a thermal heat engine.

$\eta =\frac{W}{Q}\times 100$

Here $\eta$ is the efficiency of the engine.

Substitute $2500J/cycle$ for W and $10000J/cycle$ for Q to find the value of $\eta .$

$\eta =\frac{2500J/cycle}{10000J/cycle}\times 100$

$\eta =\frac{1J/cycle}{4J/cycle}\times 100$

$\eta =25$% or

$\eta =0.25$

$\text{Hence the correct option is D}$