Question

An engineer claims to have made an engine delivering 10 kW power with fuel consumption of $1g{s}^{-1}$. The calorific value of fuel is 2 $kcal{g}^{-1}$. This claim is

• A. valid
• B. invalid
• C. dependent on engine design
• D. dependent on load

Answer 1

Answer: (B)

$P_{output}=10kW$
$p_{input}=2\times 10^{3}cal{g}^{-1}\times 1g{s}^{-1}$
= 2 $\times 10^{3}cal{s}^{-1}$
= $2\times 10^3\times 4.2J{s}^{-1}$
=8.4 kW
As,$P_{output}>P_{input}$, hence it is never possible