When cut-off ratio is __________ the efficiency of Diesel cycle approaches to Otto cycle efficiency.
A. Zero
B. $$\frac{1}{5}$$
C. $$\frac{4}{5}$$
D. 1
Answer: Option A
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Related Questions on Engineering Thermodynamics
Addition of heat at constant pressure to a gas results in
A. Raising its temperature
B. Raising its pressure
C. Raising its volume
D. Raising its temperature and doing external work
Which of the following items is not a path function?
A. Heat
B. Work
C. Kinetic energy
D. Thermal conductivity
An actual engine is to be designed having same efficiency as the Carnot cycle. Such a proposition is
A. Feasible
B. Impossible
C. Possible
D. Possible, but with lot of sophistications
The absolute zero pressure can be attained at a temperature of
A. 0°C
B. -273°C
C. 273 K
D. None of these
Correct answer is D
cut-off and cut-off ratio are two different terms, there is no cut-off in Otto cycle (i.e. cut-off is zero but cut-off ratio is one because heat is being added at constant volume so the ration of volumes is one). Now in case of diesel cycle, normally there is cut-off i.e. cut-off ratio is greater than one. As this ratio decreases and becomes equal to one (just like Otto cycle), it behaves like Otto cycle and its efficiency approaches to Otto cycle.
Shortly speaking when cut-off is ZERO or cut-off ration is ONE, efficiency of diesel cycle becomes equal to Otto cycle
in open cycle gas turbine power plant, there is no condenser used. the expanded gases are directly sent to atmosphere and not routed back to the same cycle (this is why it is called open cycle turbine power plant), therefore Option D can never be correct answer
Answer is one not zero.