The temperature of source and sink of a heat engine are $${127^ \circ }C$$ and $${27^ \circ }C$$ respectively. An inventor claims its efficiency to be $$26\% ,$$ then:
A.
it is impossible
B.
it is possible with high probability
C.
it is possible with low probability
D.
data are insufficient.
Answer :
it is impossible
Solution :
$$\eqalign{
& \eta = 1 - \frac{{300}}{{400}} = \frac{{100}}{{400}} = \frac{1}{4} \cr
& \eta = \frac{1}{4} \times 100 = 25\% \cr} $$
Hence, it is not possible to have efficiency more than $$25\% .$$
Releted MCQ Question on Heat and Thermodynamics >> Thermodynamics
Releted Question 1
An ideal monatomic gas is taken round the cycle $$ABCDA$$ as shown in the $$P - V$$ diagram (see Fig.). The work done during the cycle is
If one mole of a monatomic gas $$\left( {\gamma = \frac{5}{3}} \right)$$ is mixed with one mole of a diatomic gas $$\left( {\gamma = \frac{7}{5}} \right)$$ the value of $$\gamma $$ for mixture is
A closed compartment containing gas is moving with some acceleration in horizontal direction. Neglect effect of gravity. Then the pressure in the compartment is
A gas mixture consists of 2 moles of oxygen and 4 moles of argon at temperature $$T.$$ Neglecting all vibrational modes, the total internal energy of the system is