Quiz: Mechanical Engineering:Miscellaneous

Quiz: Mechanical Engineering

Exam: NLC (GET)

Topic: Miscellaneous

Each question carries 1 mark.

Negative marking: 1/4 mark

Time: 10 Minute

Q1. Reversible adiabatic process is also called

(a) Isothermal process

(b) Isochoric process

(d) none of these

L1Difficulty 3
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Q2. Stirling Cycle consists of

(a) Two isochoric process and two isobars

(b) Two isothermal process and two isobars

(d) Two isochoric process and two isentropic process

L1Difficulty 3

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Q3. Prandtl number is

(a) 〖(Hydrodynamic boundary layer / thermal boundary layer)〗^3
(b) 〖(Thermal boundary layer /Hydrodynamic boundary layer)〗^3

(d) None of these

L1Difficulty 3

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Q4. Photochemical smog is mainly due to

(a) and HC

(b) CO and

(d) Soot and PM

L1Difficulty 3

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Q5. When a boat enters river from a sea, one can expect

(a) to rise a little

(b) to fall a little

(d) depends upon boat density

L1Difficulty 3

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Q6. In a two-dimensional problem, the state of pure shear at a point is characterized by

(a) ϵx=ϵy and γxy=0
(b) ϵx=2ϵy and γxy≠0
(c) ϵx=ϵy and γxy≠0
(d) ϵx= 0.5ϵy and γxy=0

L1Difficulty 3

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Q7. Euler’s formula holds good only for

(a) Short column

(b) Both short and long column

(d) Long column

L1Difficulty 3

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Q8. If velocity reduction ratio is above 100 then we use

(a) Spur gear

(b) Worm and worm gear

(d) Bevel gear

L1Difficulty 3

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Q9. Following gases are used in TIG welding

(a) Argon and helium

(b) and

(d) Helium and Neon

L1Difficulty 3

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Q10.Most commonly used material, casted by cold chamber die casting

(a) Lead

(b) Zinc

(d) Silver

L1Difficulty 3

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Solutions

S1. Ans (c)

Sol. A Reversible Adiabatic Process is also known as Isentropic Process. It is an idealized thermodynamic process which is adiabatic and in which the work transfers of the system are frictionless; there is no transfer of heat or of matter and the process is reversible.

S2. Ans (c)

S3. Ans (a)

S4. Ans (a)

Sol. Photochemical smog is produced when pollutants from the combustion of fossil fuels react with sunlight. The energy in the sunlight converts the pollutants into other toxic chemicals. In order for photochemical smog to form, there must be other pollutants in the air, specifically nitrous oxides and other volatile organic compounds (VOCs).

S5. Ans (b)

Sol. Due to density of sea water is more than that of river water, hence more volume of boat has to be sunk in the river water than that in sea water.so floor level will fall of boat in sea water.

S6. Ans.(c)

Sol. Pure shear strain condition depicts, shear strain and normal strain

S7. Ans.(d)

Sol. As long column fails in buckling only, Euler formula also derived at the same assumption.

S8. (b)

Sol. Refer the table below,

Sr.no.	Type of gear	Normal speed ratio	Efficiency
1	Spur	1:1 to 6:1	94 to 98
2	Helical	10:1	94 to 98
3	Straight bevel	5: 1	93 to 97
4	Spiral bevel	4: 1	95 to 99
5	Worm	75: 1 to 100: 1	50 to 60
6	Hypoid	10: 1 to 100: 1	80 to 95
7	Cycloid	10: 1 to 100: 1	75 to 85

S9. Ans.(a)

S10. Ans.(c)

Sol. As metal with high melting point cannot be casted by hot chamber die casting due to die material design temperature limit. In the above options, Aluminium has melting point is about 660 which is more than other metal (given in option).In cold chamber die casting furnace and crucible are separate parts, apart from die.