Quiz: Mechanical Engineering 1 May 2020

Quiz: Mechanical Engineering
Exam: NLC-GET
Topic: Miscellaneous

Each question carries 1 mark
Negative marking: 1/4 mark
Time: 10 Minutes
Q1. 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
L1Difficulty 3
QTags Mechanical
QCereator Paper Maker 10

Q2. Davis steering gear consists of __________.
(a) Sliding pairs
(b) Turning pairs
(c) Rolling pairs
(d) Higher pairs
L1Difficulty 3
QTags Mechanical
QCereator Paper Maker 10

Q3. Moisture in a refrigerant system is removed by ________.
A. Driers
B. Filter driers
C. Desiccants
(a) only A
(b) only B
(c) only C
(d) A, B and c
L1Difficulty 3
QTags Mechanical
QCereator Paper Maker 10

Q4. Lithium bromide in vapour absorption refrigeration system is used as ___________.
(a) refrigerant
(b) cooling substance
(c) auxiliary refrigerant
(d) absorbent
L1Difficulty 3
QTags Mechanical
QCereator Paper Maker 10

Q5. During sensible cooling process __________.
(a) specific humidity remains constant
(b) specific humidity increases
(c) specific humidity decreases
(d) specific humidity is unpredictable
L1Difficulty 3
QTags Mechanical
QCereator Paper Maker 10

Q6. One dimensional flow is _______.
(a) restricted to flow in a straight line
(b) uniform flow
(c) one which neglects changes in a transverse direction
(d) the most general flow
L1Difficulty 3
QTags Mechanical
QCereator Paper Maker 10

Q7. Alloy steel as compared to carbon steel is more ____________.
A. tough
B. brittle
C. fatigue resistance
(a) only A
(b) only B
(c) only C
(d) None of these
L1Difficulty 3
QTags Mechanical
QCereator Paper Maker 10

Q8. The non-traditional machining process that essentially requires vacuum is
(a) electron beam machining
(b) electro chemical machining
(c) electro chemical discharge machining
(d) electro discharge machining
L1Difficulty 3
QTags Mechanical
QCereator Paper Maker 10

Q9. The part of a gating system which regulates the rate of pouring of molten metal is
(a) pouring basin
(b) runner
(c) choke
(d) ingate
L1Difficulty 3
QTags Mechanical
QCereator Paper Maker 10

Q10. Couette flow is characterized by
(a) steady. incompressible, laminar flow through a straight circular pipe
(b) filly developed turbulent flow through a straight circular pipe
(c) steady, incompressible, laminar flow between two fixed parallel plates
(d) steady. incompressible, laminar flow between one fixed plate and the other moving with a constant velocity
L1Difficulty 3
QTags Mechanical
QCereator Paper Maker 10

Solutions

S1. Ans(d)
Sol. A system is said to be in equilibrium when system has achieved all the three equilibrium as given below Thermal equilibrium, Mechanical equilibrium, Chemical equilibrium.

S2. Ans(a)
Sol. Davis steering system or Davis steering gear is the most used power steering system. Almost all cars are installed with the power steering system. This is a type of side pivot steering mechanism which has only sliding pair system.

S3. Ans(b)
Sol. To avoid entry of moisture content in compressor moisture in a refrigerant system is removed by filter driers.

S4. Ans(d)
Sol. Lithium bromide in vapour absorption refrigeration system is used as absorbent.

S5. Ans(a)
Sol. Sensible heat is the energy in the air due to the temperature of the air and the latent heat is the energy in the air due to the moisture of the air. So, for sensible cooling no change in moisture content hence specific humidity remain constant.

S6. Ans(c)
Sol. Term one dimensional, two dimensional and three dimensional flow refers to the number of space coordinated required to describe a flow.

S7. Ans(d)
Sol. Alloy steel is a type of steel that has presence of certain other elements apart from iron and carbon. Commonly added elements in alloy steel are manganese, silicon, boron, chromium, vanadium and nickel. The quantity of these metals in alloy steel is primarily dependent upon the use of such steel. Normally alloy steel is made to get desired physical characteristics in the steel. Carbon steel is also known as plain steel and is an alloy of steel where carbon is the main constituent and no minimum percentage of other alloying elements is mentioned. Carbon steel is not stainless steel as it is classified under alloy steels. As the name implies, carbon content is increased in the steel making it harder and stronger through application of heat treatments. However, addition of carbon makes the steel less ductile. The weldability of carbon steel is low and higher carbon content also lowers the melting point of the alloy.

S8. Ans(a)
Sol. In electron- beam machining, vacuum conditions are required for material removal, because electrons can ionise the presence air inside the chamber. So, we created the vacuum inside the chamber.

S9. Ans(c)
Sol. Rate of poring molten metal is regulated by choke. As, the choke area is the minimum area of the gating system, which decide the gating will be pressurized and unpressurised. Hence, choke is the part which regulates the rate of pouring.

S10. Ans(d)
Sol. Couette flow is the laminar flow of a viscous fluid in the space between two parallel plates, one of which is moving relative to the other.

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