# For an ideal heat engine,

Question:

For an ideal heat engine, the temperature of the source is $127^{\circ} \mathrm{C}$. In order to have $60 \%$ efficiency the temperature of the sink should be ${ }^{\circ} \mathrm{C}$.

(Round off to the Nearest Integer)

(write modulus or absolute value of the temperature)

Solution:

$(-113)$

$\mathrm{n}=0.60=1=\frac{\mathrm{T}_{\mathrm{L}}}{\mathrm{T}_{\mathrm{H}}}$

$\frac{\mathrm{T}_{\mathrm{L}}}{\mathrm{T}_{\mathrm{H}}=0.4 \Rightarrow \mathrm{T}_{\mathrm{L}}}=0.4 \times 400$

$=160 \mathrm{~K}$

$=-113^{\circ} \mathrm{C}$