Thermodynamics Ques 33

33. The efficiency of an ideal heat engine working between the freezing point and boiling point of water, is

[2018]

(a) $26.8 \%$

(b) $20 \%$

(c) $12.5 \%$

(d) $6.25 \%$

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Answer:

Correct Answer: 33.(a)

Solution:

  1. (a) Efficiency of ideal heat engine, $\eta=(1-\frac{T_2}{T_1})$

Sink temperature, $T_2=100^{\circ} C=100+273=373$ $ K$

Source temperature, $T_1=0^{\circ} C=0+273=273$ $ K$

Percentage efficiency, $\% \eta=(1-\frac{T_2}{T_1}) \times 100$

$ =(1-\frac{273}{373}) \times 100=(\frac{100}{373}) \times 100=26.8 \% $