Junior Engineer • Paper-IV (Mechanical Engineering)
The oil pump is driven by the -
A)
Camshaft
B)
Alternator shaft
C)
Crankshaft via drive belt
D)
Crankshaft directly
Oil pump is driven by camshaft via gear, supplying pressurised lubricating oil.
Junior Engineer • Paper-IV (Mechanical Engineering)
Which of the following is not a part of the transmission system?
A)
Clutch
B)
Wheels
C)
Gear box
D)
Axles
Clutch, gearbox, axles transmit power; wheels are final output not part of transmission.
Junior Engineer • Paper-IV (Mechanical Engineering)
At lower temperatures and pressures, the latent heat of vaporisation of a refrigerant -
A)
Decreases
B)
Increases
C)
Remains same
D)
Depends on other factors
Saturation properties: latent heat increases as saturation temperature/pressure decreases.
Junior Engineer • Paper-IV (Mechanical Engineering)
The inlet valve of a four stroke cycle internal combustion engine remains open for -
A)
130°
B)
180°
C)
230°
D)
270°
Inlet valve opens before TDC and closes after BDC, total duration about 230 degrees.
Junior Engineer • Paper-IV (Mechanical Engineering)
Energy can neither be created nor destroyed but can be converted from one form to other is inferred from-
A)
Zeroth low of thermodynamic
B)
Basic law of thermodynamics
C)
First law of thermodynamics
D)
Second law to thermodynamics
First law of thermodynamics states energy is conserved and inter-convertible.
Junior Engineer • Paper-IV (Mechanical Engineering)
Which of the following is defined as an upraised part on the hood which directs the airflow into the engine compartment?
A)
Spoiler
B)
Wings
C)
Hood scoop
D)
Hotpipe
Hood scoop is raised opening on hood to direct air into engine compartment for cooling/ram air.
Junior Engineer • Paper-IV (Mechanical Engineering)
The moisture in a refrigerant is removed by -
A)
Evaporator
B)
Safety relieve valve
C)
Dehumidifier
D)
Driers
Filter-drier contains desiccant to absorb moisture from refrigerant circuit.
Junior Engineer • Paper-IV (Mechanical Engineering)
The tendency of a diesel engine to knock increases, if -
A)
Engine speed is increased
B)
Engine Horse Power is increased
C)
Octane number of fuel is increased
D)
Compression ratio is increased
Higher octane resists auto-ignition, increasing ignition delay and diesel knock tendency.
Junior Engineer • Paper-III (Mechanical Engineering)
The deformation per unit length is called -
A)
Tensile stress
B)
Compressive stress
C)
Shear stress
D)
Strain
Strain = ΔL/L, deformation per unit length.
Junior Engineer • Paper-III (Mechanical Engineering)
Vee-belt E-type cross-sections are generally used in -
A)
Automobiles
B)
Small Engines
C)
Heavy duty machine
D)
When driver and driven units are far off
Vee-belt E-type cross-sections are used for heavy-duty power transmission because the E section is one of the largest standard V-belt sections, capable of transmitting high power at higher belt tensions. Hence, it is suitable for heavy duty machines.
Why others are incorrect:
- b) Small Engines: small engines generally use smaller belt sections such as A or B, not E.
- a) Automobiles: automobiles typically use lighter, compact belt drives, not the large E section.
- d) When driver and driven units are far off: this depends on belt length and layout, not specifically on the E-type cross-section; the section choice is based mainly on power transmitted, not distance alone.
Junior Engineer • Paper-III (Mechanical Engineering)
Soldering iron is made of wedge shape in order to -
A)
Apply high pressure at edge
B)
Retain heat
C)
Retain solder
D)
Facilitate molecular attraction
Correct answer: C. Retain solder is the option that matches the standard principle or definition asked.
Junior Engineer • Paper-III (Mechanical Engineering)
A kinematic chain is known as a mechanism when -
A)
One of the links is fixed
B)
None of the links is fixed
C)
Two of the links are fixed
D)
All links are fixed
When one link of kinematic chain is fixed, it becomes mechanism.
Junior Engineer • Paper-III (Mechanical Engineering)
Acoilis cut into two halves, the stiffness of cut coil will be -
A)
Double
B)
Half
C)
Same
D)
None of above
Stiffness k ∝ 1/coils, halving coils doubles stiffness.
Junior Engineer • Paper-III (Mechanical Engineering)
Brazing is the process of -
A)
Joining plastic sheets
B)
Hard soldering using brass spelter
C)
Casing in brass
D)
Joining protruded sections by melting
Correct answer: B. Hard soldering using brass spelter is the option that matches the standard principle or definition asked.
Junior Engineer • Paper-III (Mechanical Engineering)
Which of the following discipline provides study of the relative motion between the parts of a machine and the forces acting on the parts?
A)
Theory of machines
B)
Applied mechanics
C)
Mechanism
D)
Kinematics
Theory of machines studies kinematics and kinetics (relative motion and forces) of machine parts.
Junior Engineer • Paper-III (Mechanical Engineering)
CNC machining centre does all the work .
A)
Milling machine
B)
Drilling machine
C)
Both milling and drilling machine
D)
Turing machine
A CNC machining centre integrates milling and drilling operations under computer control.
Junior Engineer • Paper-III (Mechanical Engineering)
Expediting function consists in keeping a watch on -
A)
Operator’s activity
B)
Flow of material and in case of trouble locate source of trouble
C)
Minimising the delays
D)
Making efficient despatching
Correct answer: B. Flow of material and in case of trouble locate source of trouble is the option that matches the standard principle or definition asked.
Junior Engineer • Paper-III (Mechanical Engineering)
Percent idle time for men or machines is found by -
A)
Work sampling
B)
Time study
C)
Method study
D)
Work study
Work sampling is used to estimate the percentage of time a man or machine spends idle, working, or in other states by taking random observations over a period. Hence, percent idle time is found by work sampling. Method study deals with improving the method of doing work, not measuring idle time. Time study determines the standard time for a task by observing and timing the work cycle, not idle percentage. Work study is the broader term that includes both method study and work measurement, but the specific technique for idle-time percentage is work sampling.
Junior Engineer • Paper-III (Mechanical Engineering)
The bending moment diagram for a simply supported beam loaded in its centre is -
A)
Arightangled triangle
B)
Anequilateral triangle
C)
Anequilateral triangle
D)
Anisosceles triangle
The question is answerable only from the beam/loading diagram; the supplied CSV contains no figure, so the exact option cannot be verified.
Junior Engineer • Paper-III (Mechanical Engineering)
Which of the following elements transfers torque and is only subjected with bending moment?
A)
Axle
B)
Clutch
C)
Brake
D)
Belt drive
Axle transmits no torque, only bending; shaft takes torsion+bending.
Junior Engineer • Paper-III (Mechanical Engineering)
The property of a material which enables it to be drawn into wires with the application of a tensile force, is called -
A)
Elasticity
B)
Plasticity
C)
Ductility
D)
Malleability
Ductility allows drawing into wires under tensile load; malleability for sheets.
Junior Engineer • Paper-III (Mechanical Engineering)
The property of material by virtue of which a body returns to its original shape after removal of the load is called -
A)
Plasticity
B)
Elasticity
C)
Ductility
D)
Malleability
Elasticity is property of returning to original shape after load removal.
Junior Engineer • Paper-III (Mechanical Engineering)
A flywheel absorbs energy during those periods of crank rotation when the tuming moment is greater than the resisting moment. The absorption is -
A)
At constant speed
B)
Accompanied by increase in speed
C)
Accompanied by decrease in speed
D)
Possible at all speeds
When driving torque > load, excess energy accelerates flywheel, so speed increases during absorption.
Junior Engineer • Paper-III (Mechanical Engineering)
IfT1, T2 are the respective tensions in Newtons on the tight and slack side of the open belt drive in and v is the velocity in the belt in m/s, then the power transmitted by the belt drive will be given by:
A)
P=(T1-T2)
B)
P=(T1-T2)v^2
C)
P=(T1-T2)v
D)
P=(T1+T2)v
Power = (T1-T2)·v, net tangential force times velocity.
Junior Engineer • Paper-III (Mechanical Engineering)
Universal coupling is used to join two shafts -
A)
Which has lateral misalignment
B)
Whose axes intersect at a small angle
C)
Which are not in exact alignment
D)
Which is the simplest type of rigid coupling
Universal/Hooke joint connects shafts whose axes intersect at small angle with angular misalignment.
