171. Wood charcoal is produced by heating the wood at 100°C.
Yes
No
✅ The correct answer is option B.
Thermodynamics MCQs
172. According to First law of thermodynamics,
total internal energy of a system during a process remains constant
total energy of a system remains constant
workdone by a system is equal to the heat transferred by the system
internal energy, entha
✅ The correct answer is option B.
173. Which is the incorrect statement about Carnot cycle?
It is used as the alternate standard of comparison of all heat engines.
All the heat engines are based on Carnot cycle.
It provides concept of maximising work output between the two temperature limits.
all of the above
✅ The correct answer is option B.
174. A perpetual motion machine of the first kind is __________ according to first law of thermodynamics.
possible
impossible
✅ The correct answer is option B.
175. The area under the temperature-entropy curve (T – s curve) of any thermodynamic process represents
heat absorbed
heat rejected
either (a) or (b)
none of these
✅ The correct answer is option C.
176. The greater the pressure difference in throttling, the lesser is the irreversibility.
Yes
No
✅ The correct answer is option B.
177. Which of the following is the extensive property of a thermodynamic system?
Pressure
Volume
Temperature
Density
✅ The correct answer is option B.
178. The expansion ratio (r) is the ratio of (where v1 = Volume at the beginning of expansion, and v2 = Volume at the end of expansion)
✅ The correct answer is option B.
179. A cycle consisting of __________ and two isothermal processes is known as Stirling cycle.
two constant pressure
two constant volume
two isentropic
one constant pressure,
✅ The correct answer is option B.
180. The condition for the reversibility of a cycle is
the pressure and temperature of the working substance must not differ, appreciably, from those of the surroundings at any stage in the process
all the processes, taking place in the cycle of operation, must be extremely slow
the working parts of the engine must be friction free
all of the above
✅ The correct answer is option D.