Explore topic-wise MCQs in Thermodynamics.

This section includes 27 Mcqs, each offering curated multiple-choice questions to sharpen your Thermodynamics knowledge and support exam preparation. Choose a topic below to get started.

1.

ɣ for air is equal to

A. 1
B. 1.2
C. 1.3
D. 1.4
Answer» E.
Discussion
2.

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)
Answer» D. 1/(rk)^(ɣ)
Discussion
3.

The intake and exhaust processes are not considered in the p-V diagram of Otto cycle.

A. true
B. false
Answer» B. false
Discussion
4.

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
Answer» C. low power-to-volume ratio
Discussion
5.

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
Answer» C. equally efficient to
Discussion
6.

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
Answer» E.
Discussion
7.

IF_COMPRESSION_RATIO_OF_AN_ENGINE_WORKING_ON_OTTO_CYCLE_IS_INCREASED_FROM_5_TO_7,_THE_PERCENTAGE_INCREASE_IN_EFFICIENCY_WILL_BE?$

A. 2%
B. 4%
C. 8%
D. 14%
Answer» E.
Discussion
8.

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
Answer» C. equally efficient to
Discussion
9.

The_constant_volume_cycle_is_also_called$

A. Carnot cycle
B. Joule cycle
C. Diesel cycle
D. Otto cycle
Answer» E.
Discussion
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
Answer» C. low power-to-volume ratio
Discussion
11.

…£ for air is equal to$

A. 1.0
B. 1.2
C. 1.3
D. 1.4
Answer» E.
Discussion
12.

The_efficiency_of_Otto_cycle_is_given_by_(rk_is_the_compression_ratio)

A. 1/(rk)^(…£-1)
B. 1 – 1/(rk)^(ɣ)
C. 1 – 1/(rk)^(ɣ-1)
D. 1/(rk)^(…£)
Answer» D. 1/(rk)^(‚Äö√Ѭ∂¬¨¬£)
Discussion
13.

If compression ratio of an engine working on Otto cycle is increased from 5 to 6, its air standard efficiency will increase b?

A. 1%
B. 20%
C. 16.67%
D. 8%
Answer» E.
Discussion
14.

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
Answer» E.
Discussion
15.

In Otto cycle, heat addition takes place at

A. constant temperature
B. constant pressure
C. constant volume
D. none of the mentioned
Answer» D. none of the mentioned
Discussion
16.

A two-stroke engine is used in motorcycles and scooters.

A. true
B. false
Answer» B. false
Discussion
17.

The mean effective pressure of an Otto Cycle increases with an increase in

A. pressure ratio
B. compression ratio
C. temperature ratio
D. none of the mentioned
Answer» C. temperature ratio
Discussion
18.

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
Answer» D. compression stroke and expansion stroke
Discussion
19.

The work output of theoretical Otto cycle

A. increases with increase in compression ratio
B. increases with increase in pressure ratio
C. both of the mentioned
D. none of the mentioned
Answer» D. none of the mentioned
Discussion
20.

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
Answer» B. below, above
Discussion
21.

The thermal efficiency of theoretical Otto cycle

A. decreases with increase in compression ratio
B. increases with decrease in compression ratio
C. does not depends upon the pressure ratio
D. none of the mentioned
Answer» D. none of the mentioned
Discussion
22.

The spark plug fires shortly before the ____ stroke.

A. compression
B. expansion
C. intake
D. exhaust
Answer» C. intake
Discussion
23.

The Otto cycle consists of

A. two constant pressure processes and two constant volume processes
B. two constant pressure and two constant entropy processes
C. two constant volume processes and two constant entropy processes
D. none of the mentioned
Answer» C. two constant volume processes and two constant entropy processes
Discussion
24.

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
Answer» E.
Discussion
25.

The efficiency of an Otto cycle is increased by increasing

A. pressure ratio
B. compression ratio
C. temperature ratio
D. none of the mentioned
Answer» C. temperature ratio
Discussion
26.

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
Answer» D. none of the mentioned
Discussion
27.

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
Answer» C. vapour power cycle of CI engine
Discussion