91. It is __________ to construct an engine working on a cyclic process, whose sole purpose is to convert heat energy into work.
possible
impossible
✅ The correct answer is option B.
Thermodynamics MCQs
92. The __________ is obtained when carbonisation of coal is carried out at 500° to 700° C.
soft coke
hard coke
pulverised coal
bituminous coal
✅ The correct answer is option A.
93. It is __________ to make an engine working on a Carnot cycle.
possible
impossible
✅ The correct answer is option B.
94. The main cause for the irreversibility is
mechanical and fluid friction
unrestricted expansion
heat transfer with a finite temperature difference
all of the above
✅ The correct answer is option D.
95. According to Kelvin-Planck’s statement, a perpetual motion of the __________ is impossible.
first kind
second kind
✅ The correct answer is option B.
96. The standard value of atmospheric pressure taken at sea level is
1.013 bar
760 mm of Hg
1013 x 102 N/m2
all of these
✅ The correct answer is option D.
97. The efficiency of Ericsson cycle is __________ Carnot cycle.
greater than
less than
equal to
✅ The correct answer is option C.
98. The heat supplied to the gaS at constant volume is (where m = Mass of gas, cv = Specific heat at constant volume, cp = Specific heat at constant pressure, T2 – T1 = Rise in temperature, and R = Gas constant)
mR(T2 – T1)
mcv(T2 – T1)
mcp(T2 – T1)
mcp(T2 + T1)
✅ The correct answer is option B.
99. One reversible heat engine operates between 1600 K and T2 K and another reversible heat engine operates between T2 K and 400 K. If both the engines have the same heat input and output, then temperature T2 is equal to
800K
1000K
1200K
1400K
✅ The correct answer is option A.