196. During base load operation, the best method of controlling compressor is ___________________?
A. start-stop motor
B. constant speed unloader
C. relief valve
D. variable speed
E. none of the above

197. The volumetric efficiency of a compressor falls roughly as follows for every 100 m increase in elevation___________________?
A. 0.1%
B. 0.5%
C. 1.0%
D. 5%
E. 10%.

198. In a compressor, free air delivered is the actual volume delivered at the stated pressure reduced to ____________________?
A. N.T.P. conditions
B. intake temperature and pressure conditions
C. 0°C and 1 kg/cm2
D. 20°C and 1 kg/cm2
E. none of the above

199. The advantage of multistage compression over single stage compression is ________________?
A. lower power consumption per unit of air delivered
B. higher volumetric efficiency
C. decreased discharge temperature
D. moisture free air
E. all of the above

200. As the value of index ‘«’ is decreased, the volumetric efficiency will___________________?
A. increase
B. decrease
C. remain unaffected
D. may increase/decrease depending on compressor clearance
E. none of the above

NOTE
IF YOU THINK ANY OF THE MCQ ABOVE IS WRONG.
PLEASE COMMENT WITH CORRECT ANSWER AND ITS DETAIL EXPLANATION IN COMMENT BOX.
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201. The indicated work per unit mass of air delivered is___________________?
A. directly proportional to clearance volume
B. greatly affected by clearance volume
C. not affected by clearance volume
D. inversely proportional to clearance volume

202. The ratio of isentropic work to Euler work is known as_____________________?
A. pressure coefficient
B. work coefficient
C. polytropic reaction
D. slip factor
E. compressor efficiency

203. Phenomenon of choking in compressor means __________________?
A. no flow of air
B. fixed mass flow rate regardless of pressure ratio
C. reducing mass flow rate with increase in pressure ratio
D. increased inclination of chord with air steam
E. does not occur

204. Diffuser in a compressor is used to _____________________?
A. increase velocity
B. make the flow stream-line
C. convert pressure energy into kinetic energy
D. convert kinetic energy into pressure energy
E. increase degree of reaction

205. For supplying intermittent small quantity of air at high pressure, following compressor is best suited__________________?
A. centrifugal
B. reciprocating
C. axial
D. screw
E. turbo jet

206. Which is false statement about advantages of multistage compressor in comparison to single stage compressor_________________?
A. less power requirement
B. better mechanical balance
C. less loss of air due to leakage past the cylinder
D. more effective lubrication
E. lower volumetric efficiency

207. For minimum work in multistage compression, assuming same index of compression in all stages_________________?
A. work done in first stage should be more
B. work done in subsequent stages should increase
C. work done in subsequent stages should decrease
D. work done in all stages should be equal
E. work done in any stage is no criterion for minimum work but depends on other factors

208. The volumetric efficiency of a compressor falls roughly as follows for every 5°C increase in atmospheric temperature__________________?
A. 0.1%
B. 0.5%
C. 1%
D. 5%
E. 10%.

209. The criterion of the thermodynamic efficiency for rotary compressor is_________________?
A. isentropic compression
B. isothermal compression
C. polytropic compression
D. any one of the above
E. none of the above

210. For a two stage compressor* if index of compression for higher stage is greater than index of compression for lower stage, then the optimum pressure as compared to ideal case will___________________?
A. increase
B. decrease
C. remain unaffected
D. other factors control it
E. unpredictable

NOTE
IF YOU THINK ANY OF THE MCQ ABOVE IS WRONG.
PLEASE COMMENT WITH CORRECT ANSWER AND ITS DETAIL EXPLANATION IN COMMENT BOX.
THANK YOU

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