Mechanical Engineering Moddel mcq for Upcoming Exam.
01. In Rankine cycle, the work output from the turbine is given by __________.
A. change of internal energy between inlet and outlet
B. change of enthalpy between inlet and outet
C. change of entropy between inlet and outlet
D. change of temperature between inlet and outlet
Correct Answer : B
02. If a reheater is added to a Rankine Cycle, then usually ___________.
A. the net work increases and dryness fraction at the exit of turbine increases.
B. the net work and efficiency decrease
C. the net work remains same and efficiency increases
D. the net work increases and efficiency remains same
Correct Answer : A
Reheat Rankine Cycle is essentially a modification of simple Rankine cycle.
In reheating the dryness fraction of steam at the exit increases and also net work increases.
The thermal efficiency may increase or may decrease depending upon the mean temperature of heat addition.
03. In an axial flow compressor, when the degree of reaction is 50%, it implies that
A. Work done is compression will be the least
B. 50% stages of the compressor will be ineffective
C. Pressure after compression will be optimum
D. The compressor will have symmetrical blades
Correct Answer : D
04. Which type of compressor is commonly used in a gas turbine plant?
A. Reciprocating compressor
B. Screw compressor
C. Multistage axial flow compressor
D. Either (A) & (B)
Correct Answer : C
Multistage axial flow compressor is the compressor in practical usage in a gas turbine plant.
05. The psychrometric chart graphically represents
A. Interrelation of air temperature and moisture.
B. Interrelation of air pressure and moisture.
C. Interrelation of volume and temperature.
D. Interrelation of pressure and temperature.
Correct Answer : A
The atmosphere is a mixture of air (oxygen and nitrogen) and water vapour. Psychrometry is the study of moist air and of the changes in its conditions.
06. In psychrometric chart, which lines have highest slope?
A. WBT (wet bulb temp.)
B. h. (sp. Enthalpy)
C. Relative humidity
D. v (specific volume)
Correct Answer : D
In psychrometric chart, specific volume lines have highest slope.
07. In a psychrometric chart, relative humidity lines are:
A. Curved
B. Inclined and straight but non-uniformly spaced
C. Horizontal and non-uniformly spaced
D. Horizontal and uniformly spaced
Correct Answer : A
In psychrometric chart, relative humidity (RH) lines are curved having positive slope from zero to infinite.
08. Which of the following properties of refrigerant is not desirable?
A. Low boiling point
B. High critical temperature
C. Specific volume at the inlet of compressor must be high
D. Low Viscosity
Correct Answer : C
Work input to the compressor is directly dependent upon the volume at the inlet of compressor.
More the volume, more will be the work.
Thus, it is undesirable.
All others are desirable.
09. The Mollier diagram of a pure substance is a
A. h-s diagram
B. T-s diagram
C. P-h diagram
D. h-P diagram
Correct Answer : A
The Mollier diagram of a pure substance is enthalpy(h) vs. entropy(s) diagram.
So, the correct option is (a).
10. The cutting force in punching and blanking operations mainly depends on
A. the modulus of elasticity of metal.
B. the shear strength of metal
C. the bulk modulus of metal
D. the yield strength of metal
Correct Answer : B.
11. Which of the following welding technique requires vacuum for its application?
A. Laser-Beam welding
B. Electron-Beam welding
C. Atomic Hydrogen welding
D. Electroslag welding
Correct Answer : B
Electron beam welding is a fusion joining process that produces electron beam in a vacuum which is impinged with high energy to heat the weld joint.
So, the correct option is (b).
12. Riser is provided to compensate ____.
A. Only liquid shrinkage
B. Only solidification shrinkage
C. Both liquid and solid shrinkage
D. Both liquid and solidification shrinkage
Correct Answer : D
Both liquid and solidification shrinkage can be compensated by providing the riser. Solid shrinkage is compensated by increasing the size of pattern in the form of shrinkage allowance.
So, the correct option is (d).
13. Relation between velocity and radius in Forced vortex motion is
A. Inversely proportional
B. Directly proportional
C. No relation exists
D. Constant
Correct Answer : B
14. An adjustable blade turbine is called _______.
A. Propeller Turbine
B. Kaplan Turbine
C. Pelton Turbine
D. Banki Turbine
Correct Answer : B
A Kaplan turbine is basically a propeller with adjustable blades inside a tube.
It is a type of axial flow reaction turbine.
15. Specific speed of a pump depends upon_____.
A. Speed, head and discharge
B. Discharge and power
C. Speed and head
D. Speed, power and head
Correct Answer : A
16. When two systems are in thermal equilibrium with a third system, they are in thermal equilibrium with each other, this law is known as
A. Zeroth law of thermodynamics
B. First law of thermodynamics
C. Second law of thermodynamics
D. None of these
Correct Answer : A
The zeroth law of thermodynamics states that if two thermodynamic systems are each in thermal equilibrium with a third one, then they are in thermal equilibrium with each other.
17. A system will be thermodynamic equilibrium only if it is in __________.
A) Thermal equilibrium
B) Mechanical equilibrium
C) Chemical equilibrium
A. only A
B. only B
C. only C
D. A, B and C
Correct Answer : D
A system is said to be in equilibrium when system has achieve all the four equilibrium as given below
Thermal equilibrium,
Mechanical equilibrium,
Chemical equilibrium
No phase change.
18. Newton’s first law of motion is also known as
A. the Law of Conservation of Momentum
B. the Law of Inertia
C. gravity
D. Coulomb’s law
Correct Answer : B
According to first law of motion an object will remain at rest or in a uniform state of motion unless that state is changed by an external force. This is also known as the law of inertia.
19. Bearings are compared based on their load carrying capacity, therefore the bearing whose load carrying capacity is independent of speed is;
A. Hydrostatic bearing
B. Hydrodynamic bearing
C. Rolling contact bearing
D. Sliding contact bearing
Correct Answer : A
For hydrostatic bearing, the load carrying capacity is independent of speed, as constant thickness of fluid film is presented by external pump throughout the operation.
20. A wire rope is designated by 8×19, find the no. of wire in each strand ______.
A. 8
B. 19
C. 152
D. Can’t be determined
Correct Answer : B
Designation of wire rope: m×n
Where m: no. of strands
n: no. of wire in each strand.
21. Which of the following is not a hardness test.
A. Brinells test
B. Vicker’s test
C. Izod test
D. Knoop test
Correct Answer : C
Izod test is a toughness test whereas all others are Hardness measuring test.
22. The phenomenon of slow extension of materials having constant load, i.e. increasing with the time is called
A. Creep
B. Yielding
C. Breaking
D. Plastic flow
Correct Answer : A
creep (sometimes called cold flow) is the tendency of a solid material to move slowly or deform permanently under the influence of persistent mechanical stresses. It can occur as a result of long-term exposure to high levels of stress that are still below the yield strength of the material.Since there is a constant load and stress increases with time, phenomenon is Creeping
23. Diamond Pyramid Hardness is related to __________.
A. Brinell Hardness Test
B. Vickers Hardness Test
C. Rockwell Hardness Test
D. None of above
Correct Answer : B
The Rockwell hardness test is used for finding hardness of ferrous and non ferrous metals.
24. When a rectangular beam is loaded transversely, the maximum tensile stress is developed on the
A. Top layer
B. Bottom layer
C. Neutral axis
D. At any cross section
Correct Answer : A
When a rectangular beam is loaded transversely, the maximum tensile stress is developed on the top layer.
25. The shape of a cantilever beam for uniformly distributed load will be
A. Straight line
B. Parabolic
C. Elliptical
D. None of these
Correct Answer : B
The shape of a cantilever beam for uniformly distributed load will be parabolic.
26. Which of the following is a dimensionless quantity?
A.Stress
B. Strain
C. Poisson’s ratio
D. Both (b) and (c)
Correct Answer : D
Both strain and Poisson’s ratio is a dimensionless quantity.
27. The bending stress is zero at
A. Top fibre
B. Bottom fibre
C. Neutral axis
D. Between top fibre and neutral axis
Correct Answer : C
28. The method of obtaining different mechanism by fixing different links of a kinematic chain is known as:
A. Structure
B.Mechanism
C. Inversion
D. None of these
Correct Answer : C
29. Permanent deformation of material with respect to time due to constant load and variable temperature is known as _________.
A. Elasticity
B. Isotropy
C. Hardness
D. Creep
Correct Answer : D
Creep may be defined as a time-dependent permanent deformation at elevated temperature and constant stress.
Creep deformation occurs due to grain-boundary sliding, the more grain boundary area, the easier creep deformation will be. Thus, Creep deformation and creep strength are a grain-size sensitive property.
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