Thermodynamics Questions and Answers – Otto Cycle

This set of Thermodynamics Multiple Choice Questions & Answers (MCQs) focuses on “Otto Cycle”.

1. The Otto cycle is the
a) air standard cycle of CI engine
b) air standard cycle of SI engine
c) vapour power cycle of CI engine
d) vapour power cycle of SI engine
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2. In a four-stroke internal combustion engine,
a) the piston does four complete strokes within cylinder
b) for each cycle, the crankshaft completes two revolutions
c) both of the mentioned
d) none of the mentioned
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3. The correct sequence of strokes in a four-stroke SI engine is
a) intake->compression->exhaust->expansion
b) intake->expansion->compression->exhaust
c) intake->exhaust->compression->expansion
d) intake->compression->expansion->exhaust
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4. The spark plug fires shortly before the ____ stroke.
a) compression
b) expansion
c) intake
d) exhaust
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5. The pressure in cylinder is ____ the atmospheric value during exhaust stroke and ____ it during intake stroke.
a) above, below
b) below, above
c) equal to, equal to
d) equal to, above
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6. In a two-stroke engine, the four functions performed in SI engine are done in which two strokes?
a) expansion stroke and compression stroke
b) intake stroke and exhaust stroke
c) compression stroke and power stroke
d) compression stroke and expansion stroke
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7. A two-stroke engine is used in motorcycles and scooters.
a) true
b) false
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8. In a two-stroke engine,
a) the crankcase is sealed
b) the outward motion of piston is used to pressurize the air-fuel mixture
c) the intake and exhaust valves are replaced by opening in lower part of cylinder wall
d) all of the mentioned
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9. The two-stroke engine is ____ the four-stroke engine.
a) more efficient than
b) less efficient than
c) equally efficient to
d) none of the mentioned
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10. The two-stroke engine is
a) simple and expensive
b) high power-to-weight ratio
c) low power-to-volume ratio
d) all of the mentioned
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11. The intake and exhaust processes are not considered in the p-V diagram of Otto cycle.
a) true
b) false
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12. The efficiency of Otto cycle is given by (rk is the compression ratio)
a) 1/(rk)^(ɣ-1)
b) 1 – 1/(rk)^(ɣ)
c) 1 – 1/(rk)^(ɣ-1)
d) 1/(rk)^(ɣ)
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13. Which of the following statement is true?
a) efficiency of air standard cycle is a function of compression ratio and temperature levels
b) higher the compression ratio, higher will be the efficiency
c) efficiency is dependent on the temperature levels at which the cycle operates
d) all of the mentioned
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14. ɣ for air is equal to
a) 1.0
b) 1.2
c) 1.3
d) 1.4
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15. The Otto cycle consists of
a) two reversible isotherms and two reversible isobars
b) two reversible isochores and two reversible adiabatics
c) two reversible isotherms and two reversible isochores
d) two reversible isobars and two reversible adiabatics
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Sanfoundry Global Education & Learning Series – Thermodynamics.
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