Quiz: Mechanical Engineering 22 May 2020

Quiz: Mechanical Engineering
Exam: NLC GET
Topic: Miscellaneous
Each question carries 1 mark
Negative marking: 1/3 mark
Time: 10 Minutes

Q1. The maximum force which acts on the connecting rod is
(a) Force due to gas pressure
(b) Force due to inertia of piston
(c) Force due to friction of connecting rod
(d) Force due to crank pin

Q2. Strain rosettes are generally used for
(a) measurement of load
(b) measurement of shear strain
(c) measurement of longitudinal strain
(d) measurement of resilience

Q3. Toggle mechanism have following applications except
(a) Stone crushers
(b) Gear cutting
(c) Embossing presses
(d) Switches

Q4. Match the following List-I and List-II and select the correct answer using the codes
given below the lists:
List-I
A. Pantograph
B. Single slider crank chain
C. Double slider crank chain
D. Straight line motion
List-II
1. Scotch yoke mechanism
2. Double lever mechanism
3. Tchebicheff mechanism
4. Double crank mechanism
5. Hand pump
Codes:
A B C D
(a) 4 3 5 1
(b) 2 5 1 3
(c) 2 1 5 3
(d) 4 5 2 1

Q5. The delay period in CI engine depends upon
1. Temperature and pressure in the cylinder at the time of injection
2. Strength of fuel mixture
3. Relative velocity between the fuel injection and air turbulence pressure of residual gas
4. Engine output
Select the correct answer:
(a) 1, 2, 3 and 4
(b) 1, 2 and 3
(c) 1, 2 and 4
(d) 1, 3 and 4

Q6. At breakeven point:
(a) Sales revenue > total cost
(b) Sales revenue = total cost
(c) Sales revenue < total cost
(d) None of the above

Q7. In which of the following process, a small-diameter thick ring is expanded into a large diameter thinner ring by placing the ring between two rolls
(a) Shape rolling
(b) Tube rolling
(c) Ring rolling
(d) Continuous rolling

Q8. The instrument preferred in the measurement of highly fluctuating velocities in air flows is
(a) Pitot-static tube
(b) Propeller type anemometer
(c) Three cup anemometer
(d) Hot wire anemometer

Q9. A metal block is thrown into deep lake. As it sinks deeper in water, the buoyant force acting on it
(a) increases
(b) remains the same
(c) decreases
(d) first increases and then decreases

Q10. Match the following List-I with List-II and select the correct answer using the codes given below
List-I
A. Rigid coupling
B. Oldham’s coupling
C. Universal joint
D. Gear coupling
List-II
1. Permits greater torque capacity for a given size
2. Permits substantial angular misalignment of intersecting axes
3. Permits substantial lateral offset and little angular alignment
4. Permits almost no misalignment
Codes:
A B C D
(a) 1 2 3 4
(b) 4 2 3 1
(c) 1 3 2 4
(d) 4 3 2 1

 

SOLUTIONS

S1. Ans (a)
Sol. All of the given forces act on the connecting rod but the major force that acts on the connecting rod is the force due to gas pressure.

S2. Ans(c)
Sol. strain rosettes are generally used for measurement of longitudinal strain.
A strain gauge rosette is a term for an arrangement of two or more strain gauges that are positioned closely to measure strains along different directions of the component under evaluation. Single strain gauges can only measure strain effectively in one direction, so the use of multiple strain gauges enables more measurements to be taken, providing a more precise evaluation of strain on the surface being measured.

S3. Ans (b)
Sol. Stone crushers, embossing presses and switches works on toggle mechanism. Mechanical advantage of toggle mechanism is infinite or very large.

S4. Ans (b)
Sol. Pantograph utilizes double lever mechanism, Hand pump utilizes single slider crank chain, Scotch-yoke mechanism is an inversion of double slider crank chain and Tchebicheff mechanism is an approximate straight-line motion mechanism.

S5. Ans (a)
Sol. Following factors affects the delay period in CI engine
1. Temperature and pressure in cylinder
2. Engine output
3. Relative velocity of fuel injection and air turbulence
4. Strength of fuel mixture
5. Compression ratio

S6. Ans(b)
Sol. Breakeven point- The breakeven point is the level of production at which the costs of production equal the revenues for a product. At breakeven point, profit will be zero even there is no loss.
Which means sales revenue is equal to total cost.
Sales revenue = total cost

S7. Ans.(c)
Sol. Ring rolling is an operation of metal forming in which a small diameter, thick ring is
converted into large diameter, thinner ring by placing the ring between two rolls.

S8. Ans (d)
Sol. Hot wire anemometer is used for the measurement of highly fluctuating velocities in air. This can be done by measuring the heat loss of the wire which is placed in the fluid stream. The wire is heated by electrical current. The hot wire when placed in the stream of the fluid, in that case, the heat is transferred from wire to fluid, and hence the temperature of wire reduces. The resistance of wire measures the flow rate of the fluid which is the function of heat loss from the wire and change in the resistance of wire.

S9. Ans (b)
Sol. As buoyant force depends only on the displaced volume of fluid by the submerged or floating body according to Archimedes principle. So, volume displaced by the metal block will remain constant from when it sinks in the fluid till it sinks deeper, hence, the buoyant force on the metal block remains same.

S10. Ans (d)
Sol.
• Rigid coupling permits almost no misalignment.
• Oldham’s coupling permits substantial lateral offset and little angular alignment.
• Universal joint permits substantial angular misalignment of intersecting axes.
• Gear coupling permits greater torque capacity for a given size.

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.

Quiz: Electrical Engineering 6 April 2020

Quiz: Electrical Engineering

Exam: NLC

Topic: Miscellaneous

 

Each question carries 1 mark.

Negative marking: 1/4 mark

Time: 10 Minute

 

Q1. Which semiconductor device behaves like two SCR’s?

(a) Triac

(b) MOSFET

(c) JEET

(d) UJT

L1Difficulty 3

QTags Semiconductors & diodes

QCreator Balwant Kumar

 

 

Q1.   A switchgear is device used for

(a) interrupting an electrical circuit

(b) switching an electrical circuit

(c) switching and controlling an electrical circuit

(d) switching, controlling and protecting the electrical circuit and equipment

L1Difficulty 3

QTags Switchgear and protection

QCreator Balwant Kumar

 

 

 

Q3.   The insulating material for a cable should have

(a) low cost

(b) high dielectric strength

(c) high mechanical strength

(d) all of the above

L1Difficulty 3

QTags Switchgear and protection

QCreator Balwant Kumar

 

 

 

 

Q4.   Cables, generally used beyond 66 kV are

(a) oil filled

(b) S.L. type

(c) belted

(d) Armoured

L1Difficulty 3

QTags Utilization of electrical energy

QCreator Balwant Kumar

 

 

Q5.      Reciprocal of permeability is

(a) reluctivity

(b) susceptibility

(c) permittivity

(d) conductance

L1Difficulty 3

QTags Basic electrical engineering

QCreator Balwant Kumar

 

 

Q6.      A transformer provides a path of magnetic flux of

(a) high conductivity

(b) high reluctance

(c) low reluctance

(d) low conductivity

L1Difficulty 3

QTags Transformer

QCreator Balwant Kumar

 

 

 

Q7.      Which of the following is not a unit of flux?

(a) Maxwell

(b) Tesla

(c) Weber

(d) All of the above

L1Difficulty 3

QTags Magnetic circuit

QCreator Balwant Kumar

 

 

Q8.      Transformer works on the principle of

(a) gauss law

  1. b) self-induction

(c) Faraday’s law of electromagnetic inductions

(d) self and mutual induction both

L1Difficulty 3

QTags Transformer

QCreator Balwant Kumar

 

 

Q9.      Which of the following statements is correct?

(a) The magnetic flux inside an exciting coil is lower than its outside surface

(b) The magnetic flux inside an exciting coil is zero

(c) The magnetic flux inside the exciting coil is greater than its outside surface

(d) The magnetic flux inside the exciting coil is same as on its outside surface

L1Difficulty 3

QTags Magnetic circuit

QCreator Balwant Kumar

 

 

Q10.      In an induction motor, the torque T is related to the supply voltage V as

(a) T  V

(b) T  V²

(c) T

(d) T

L1Difficulty 3

QTags Single phase induction motor

QCreator Balwant Kumar

 

 

Solution

 

 

S1. (a)

sol.  Triac

 

S2. (d)

SOL

In an electric power system, switchgear is the combination of electrical disconnect switches, fuses or circuit breakers used to control, protect and isolate electrical equipment. Switchgear is used both to de-energize equipment to allow work to be done and to clear faults downstream. This type of equipment is directly linked to the reliability of the electricity supply.

 

S3. (d)

Solution: The insulating materials used in cables should have the following properties:

  • High insulation resistance to avoid leakage current.
  • High dielectric strength to avoid electrical breakdown of the cable.
  • High mechanical strength to withstand the mechanical handling of cables.
  • Non-hygroscopic i.e., it should not absorb moisture from air or soil. The moisture tends to decrease the insulation resistance and hastens the breakdown of the cable. In case the insulating material is hygroscopic, it must be enclosed in a waterproof covering like lead sheath.
  • Non-inflammable.
  • Low cost so as to make the underground system a viable proposition.
  • Unaffected by acids and alkalis to avoid any chemical action

 

S4. (a)

Solution:

Cables generally used beyond 66 kV are oil filled.

 

S5. (a)

Reluctivity is reciprocal of permeability.

S6. (c)

Low reluctance

; As  increases Reluctance decreases.

 

S7. (b)

Tesla is the unit of magnetic flux density. (1 tesla = 1 wb/sq.m)

S8. (a)

Transformer works on the principle of Faraday’s law of electromagnetic inductions.

S9. (d)

Magnetic flux inside and outside surface of an exciting coil is same.

S10. (b)

Relation between torque and supply voltage of an induction motor

T  V²

 

Quiz: Electrical Engineering 3 April 2020

Quiz: Electrical Engineering

Exam: NLC

Topic: Miscellaneous

 

Each question carries 1 mark.

Negative marking: 1/4 mark

Time: 10 Minute

 

Q1. What is the most effective way to reduce the cost of power generation in a power station?

(a)By increasing the diversity factor and decreasing the load factor

(b)By increasing both the diversity factor and the load factor

(c)By decreasing both the diversity factor and the load factor

(d)By decreasing the diversity factor and increasing the load factor.

L1Difficulty 3

QTags Power generation, transmission and distribution

QCreator Balwant Kumar

 

 

Q2. The measurement of dielectric loss and power factor is done using

(a)Schering Bridge

(b)Hays Bridge

(c)Weins Bridge

(d)Wheat Stone Bridge

L1Difficulty 3

QTags Instruments & Measurements

QCreator Balwant Kumar

 

 

Q3. What is the value of total electric flux coming out of closed surface?

(a)Zero

(b)Equal to volume charge density

(c)Equal to the total charge enclosed by the surface

(d)Equal to the surface charge density

L1Difficulty 3

QTags Magnetic circuit

QCreator Balwant Kumar

 

 

Q4. The direction of rotation of hysteresis motor is determined by the:

(a)Resistivity of the rotor material.

(b)Amount of hysteresis loss.

(c)Permeability of rotor material.

(d)Position of shaded pole w.r.t main pole.

L1Difficulty 3

QTags DC Motor

QCreator Balwant Kumar

 

 

Q5. What is the dimensional representation of Power?

(a)ML2T-3

(b)M2L2T-3

(c)MLT-3

(d)M2 LT-2

L1Difficulty 3

QTags Basic electrical engineering

QCreator Balwant Kumar

 

 

 

Q6. Fermi level is the measure of

(a)Doping of electrons

(b)Probability of occupancy of electrons or holes

(c)Probability of occupancy of photons

(d)Probability of occupancy of wavelength

L1Difficulty 3

QTags Basic electrical engineering

QCreator Balwant Kumar

 

 

Q7. In order to minimize loss due to hysteresis, the magnetic material should have

(a)high resistivity

(b)low hysteresis coefficient

(c)large B-H loop area

(d)high retentivity

L1Difficulty 3

QTags Magnetic circuit

QCreator Balwant Kumar

 

 

 

Q8. Internal resistance of a cell depends on

(a)Terminal voltage

(b)Torque

(c)Current

(d)Area of the plate

L1Difficulty 3

QTags Basic electrical engineering

QCreator Balwant Kumar

 

 

Q9. FET belongs to which of the following type of device?

(a)Current controlled device

(b)Magnetic device

(c)Power controlled device

(d)Voltage controlled device

L1Difficulty 3

QTags Analog and digital electronics (electrical engineering)

QCreator Balwant Kumar

 

 

 

Q10. When ‘n’ resistances each of value ‘r’ are connected in parallel, then the resultant resistance is ‘x. when these ‘n’ resistances are connected in series, total resistance is :

(a)n2X

(b)X/n

(c)n2/X

(d)nX

L1Difficulty 3

QTags Basic electrical engineering

QCreator Balwant Kumar

 

 

Solution

 

S1. Ans(b)

Sol. The most effective way to reduce the cost of power generation in a power station by increasing

both the diversity factor and the load factor

S2. Ans(a)

Sol. Schering bridge

S3. Ans(c)

Sol. Total electric flux coming out of closed surface equals to total charge enclosed by the surface

S4. Ans(d)

Sol. Position of shaded pole w.r.t pole

S5. Ans(a)

Sol. ML2T-3

S6. Ans(b)

Sol. Probability of occupancy of electrons or holes

S7. Ans(b)

Sol. Low hysteresis coefficient

S8. Ans(d)

Sol. Area of the plate

S9. Ans(d)

Sol. FET belongs to Voltage control device

S10. Ans(a)

Sol. N2X