Explore topic-wise MCQs in Mechanical Engineering (MCQ) questions and answers.

This section includes 24 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Engineering (MCQ) questions and answers knowledge and support exam preparation. Choose a topic below to get started.

1.

Carnot cycle is

A. a reversible cycle
B. an irreversible cycle
C. practical cycle
D. none of the above
Answer» B. an irreversible cycle
Discussion
2.

A body is at a temperature T1 with certain heat capacity and a heat engine is operated between the body and a thermal heat reservoir at temperature (T0). What will be the final temperature of the body when heat engine will stop working?

A. T1
B. T0
C. (T1 + T0) / 2
D. T
Answer» C. (T1 + T0) / 2
Discussion
3.

The mean temperature of heat addition (T) in the Rankine cycle can be increased by

A. reheating the steam
B. increasing superheat
C. increasing pressure ratio between which the cycle works
D. all of the above
Answer» E.
Discussion
4.

Match the following group 1 items with group 2 items and select the correct option.(1) PMM1 ---------------------------------- (A) Heat pump(2) PMM2 ---------------------------------- (B) Violates the statement that total energy of the universe is constant(3) Reversible heat engine ---------- (C) Violates Kelvin-Planck statement(4) Carnot cycle ------------------------- (D) Reversible process

A. (1)-(A), (2)-(B), (3)-(C), (4)-(D)
B. (1)-(B), (2)-(D), (3)-(C), (4)-(A)
C. (1)-(B), (2)-(C), (3)-(A), (4)-(D)
D. (1)-(C), (2)-(D), (3)-(B), (4)-(A)
Answer» D. (1)-(C), (2)-(D), (3)-(B), (4)-(A)
Discussion
5.

The efficiency of the Carnot cycle is the function of

A. temperatures (T1, T2) between which the Carnot cycle operates
B. net work done (W
C. heat supplied (Q1) and heat rejected (Q2)
D. all of the above
Answer» B. net work done (W
Discussion
6.

How is the Helmholtz functions (F) represented?Where U represents internal energyT represents temperature S represents entropy

A. F = U + TS
B. F = U TS
C. F = UT S
D. F = UT + S
Answer» C. F = UT S
Discussion
7.

How is the Gibbs function (G) represented? Where U represents internal energyT represents temperature S represents entropy

A. G = U + pV + TS
B. G = U pV TS
C. G = U + pV TS
D. G = U pV + TS
Answer» D. G = U pV + TS
Discussion
8.

Assume that a reversible heat engine is operating between a source at T1 and a sink at T2. If T2 decreases, the efficiency of the heat engine______

A. decreases
B. increases
C. remains constant
D. none of the above
Answer» C. remains constant
Discussion
9.

What is the relation between thermodynamic probability and entropy?

A. thermodynamic probability increases with entropy
B. thermodynamic probability decreases with entropy
C. thermodynamic probability does not change with change in with entropy
D. none of the above
Answer» B. thermodynamic probability decreases with entropy
Discussion
10.

Which among the following engines is NOT the type of aircraft gas turbine which works on

A. turbojet
B. turbofan
C. turboprop
D. none of the above
Answer» E.
Discussion
11.

At the state of perfect order of pure crystalline substance, how is the zero entropy defined?

A. entropy at 0 C temperature
B. entropy at absolute zero temperature
C. entropy at the freezing point of the substance
D. none of the above
Answer» C. entropy at the freezing point of the substance
Discussion
12.

In a mixture of ideal gases of volume and temperature , what is the pressure exerted by each individual gas if it occupies the total volume alone at temperature called?

A. individual pressure
B. divided pressure
C. partial pressure
D. total pressure
Answer» D. total pressure
Discussion
13.

The statement consists that ____.

A. to fix state of pure substance of a given mass, the system should be in equilibrium
B. to fix state of pure substance of a given mass, any two independent intensive properties of the substance should be specified
C. both a. and b. conditions should be satisfied
D. none of the above
Answer» D. none of the above
Discussion
14.

A platinum resistance thermometer has a resistance of 2 ohm at 0&deg C and 3 ohm at 100&deg C. What will be the temperature when resistance indicates 5 ohm?

A. 300&deg C
B. 200&deg C
C. 350&deg C
D. 400&deg C
Answer» B. 200&deg C
Discussion
15.

A closed feedwater heater system

A. has high heat transfer capacity
B. requires pump at each heater to handle the large feedwater stream
C. requires only single pump regardless of the number of heaters
D. does not require any pump as the extracted steam and feedwater are not allowed to mix
Answer» D. does not require any pump as the extracted steam and feedwater are not allowed to mix
Discussion
16.

Which among the following statements are correct?(1) Energy is an extensive property(2) Specific energy is an extensive property (3) Energy is a point function(4) Heat capacity is an extensive property

A. Statement (1), (2) and (3)
B. Statement (1), (3) and (4)
C. Statement (2), (3) and (4)
D. Statement (1), (2), (3) and (4)
Answer» C. Statement (2), (3) and (4)
Discussion
17.

Match the following irreversibilities(1) Mechanical irreversibility ------ (A) Refrigeration cycle(2) Thermal irreversibility --------- (B) Forming of water by combination of Hydrogen and Oxygen(3) Chemical irreversibility -------- (C) Free expansion of gas in a system(4) External irreversibility --------- (D) Melting of ice cube under the sunlight

A. (1)-(A), (2)-(B), (3)-(C), (4)-(D)
B. (1)-(A), (2)-(D), (3)-(B), (4)-(C)
C. (1)-(C), (2)-(D), (3)-(A), (4)-(B)
D. (1)-(C), (2)-(D), (3)-(B), (4)-(A)
Answer» E.
Discussion
18.

A cyclic heat engine operates between a source temperature of 927 C and a sink temperature of 27 C. What will be the maximum efficiency of the heat engine?

A. 100 %
B. 80 %
C. 75 %
D. 70 %
Answer» D. 70 %
Discussion
19.

Suppose the entropy of a system increases with increase in some parameter . What will be the effect on entropy at equilibrium state of the system, when the parameter will be decreased?

A. the entropy decrease
B. the entropy increase
C. the entropy remains constant
D. Condition is wrong; entropy does not change with any parameter.
Answer» D. Condition is wrong; entropy does not change with any parameter.
Discussion
20.

How are the efficiencies of any heat engine ( ) and reversible heat engine ( ) compared, when both are operating between same heat source and same heat sink?

A. =
B. >
C. <
D. cannot say
Answer» D. cannot say
Discussion
21.

How is the efficiency of the SI engine affected by change in specific heat ratio ( ) of the working fluid?

A. the efficiency of the engine increases with increase in specific heat ratio ( ) of the working fluid
B. the efficiency of the engine decreases with increase in specific heat ratio ( ) of the working fluid
C. the efficiency of the engine does not affected by change in specific heat ratio ( ) of the working fluid
D. none of the above
Answer» B. the efficiency of the engine decreases with increase in specific heat ratio ( ) of the working fluid
Discussion
22.

When,H1 = Total heat of air entering the coil (heating or cooling)H2 = Total heat of air leaving the coil (heating or cooling)H3 = Total heat of air at the end of the process (humidification or dehumidification)then, the sensible heat factor (H2 H1) / (H3 H1) represents the process of

A. cooling and humidification
B. cooling and dehumidification
C. heating and humidification
D. heating and dehumidification
Answer» D. heating and dehumidification
Discussion
23.

In binary vapour cycle, the cycle which is operated in high pressure ratio is called as

A. bottoming cycle
B. topping cycle
C. upper cycle
D. pressure cycle
Answer» C. upper cycle
Discussion
24.

What is the drawback of the steam as a working substance in a power cycle?

A. in a vapour power cycle, maximum temperature which can be obtained with best available material is more than the critical temperature of water and requires large superheating
B. it allows only small amount of heat addition at the highest temperature
C. it requires reheat and reheater tubes are costly
D. all of the above
Answer» E.
Discussion