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Past Questions — 2016
Formula for calculating horse power per ton of refrigeration
A)
475 / COP
B)
475 * COP
C)
COP
D)
None of these
For a refrigeration system, 1 ton of refrigeration = 3.517 kW of cooling. The compressor power required depends on the COP:
Power (kW) = Refrigeration effect / COP.
Converting this to horsepower and using the standard approximation used in HVAC problems gives horse power per ton of refrigeration as 475 / COP. Therefore, option (a) is correct.
Option (b) is incorrect because horsepower increases with lower COP, not with higher COP. Option (c) is just COP itself, which is not a power formula. Option (d) is incorrect because the correct formula is listed in option (a).
An engine has a clearance volume of 100cm³ and swept volume of 800cm³. The compression ratio is
A)
7:1
B)
9:1
C)
10:1
D)
8:1
Compression ratio = (Swept volume + Clearance volume) / Clearance volume = (800 + 100) / 100 = 900 / 100 = 9. So the compression ratio is 9:1. Therefore, the correct option is (b), not (d).
In internal combustion engine the approximate percentage of the combustion heat that passes to the cylinder walls is
A)
5%
B)
10%
C)
30%
D)
60% or 75%
In an internal combustion engine, a significant portion of the fuel’s heat is lost to the cooling water and cylinder walls. The approximate heat transfer to the cylinder walls is about 30%. Hence option (c) is correct. The other options are not consistent with standard IC engine heat-balance data: 5% and 10% are too low, while 60% or 75% is too high for heat passing directly to the cylinder walls.
“A body, immersed partly or wholly in a fluid at rest, appears to lose a part of its weight, the apparent loss being equal to the weight of the fluid displace” is
A)
Archimedes’ Principle
B)
Pascal’s Law
C)
Newton’s Law of Motion
D)
None of these
The statement describes buoyancy: when a body is partly or wholly immersed in a fluid at rest, it experiences an upthrust equal to the weight of the fluid displaced. This is exactly Archimedes’ Principle. Pascal’s Law deals with transmission of pressure in fluids, and Newton’s laws are general laws of motion, so neither matches this definition.
An electrically operated device used to keep houses, offices and laboratories cool during summer and warm during winter, which not only controls temperature but also regulates humidity is
A)
Air circulator
B)
Air conditioner
C)
Air heater
D)
None of these
An air conditioner is an electrically operated device that controls both temperature and humidity, keeping indoor spaces cool in summer and warm in winter. An air circulator only moves air, and an air heater only provides heat, so they do not regulate both temperature and humidity like an air conditioner does.
A dirty exhaust and intense diesel knock from a C.I. engine is caused by
A)
High Cylinder temperature
B)
Poor fuel atomization
C)
Supplying insufficient fuel to suit the air
D)
Breaking up the injected fuel into very fine particles
In a C.I. (diesel) engine, dirty exhaust and intense diesel knock usually occur when the injected fuel does not atomize properly. Poor atomization leads to larger fuel droplets, delayed and uneven combustion, incomplete burning, and thus smoky/dirty exhaust along with sharp pressure rise causing knock. High cylinder temperature is not the primary cause here, and supplying insufficient fuel to suit the air would generally reduce smoke rather than cause it. Breaking up fuel into very fine particles is desirable because it improves combustion, so it is the opposite of the cause.
Petrol engine works on
A)
Diesel cycle
B)
Dual cycle
C)
Otto cycle
D)
None of these
A petrol engine is a spark-ignition engine, and its ideal thermodynamic cycle is the Otto cycle. The Otto cycle consists of two constant-volume processes and is the standard cycle for petrol engines. Diesel engines work on the Diesel cycle, and some engines may approximate the dual cycle, so those options are incorrect here.
The artificial withdrawal of heat, producing in a substance or within a space, a temperature lower than that which would exist under the natural influence of surrounding is known as
A)
Regeneration
B)
Refrigeration
C)
Reheating
D)
None of these
The statement defines the process of removing heat artificially to maintain a temperature below the surroundings. This is called refrigeration. Regeneration means recovering energy or material for reuse, and reheating means increasing temperature after cooling. Therefore, the correct answer is Refrigeration.
Radiator tubes are generally made of
A)
Steel
B)
Brass
C)
Cast iron
D)
Plastics
Radiator tubes are generally made of brass because it has good thermal conductivity, is corrosion-resistant, and is easy to fabricate into thin tubes. Steel is less preferred due to corrosion issues, cast iron is too heavy and not suitable for thin radiator tubes, and plastics are not used for radiator tubes in conventional automobile radiators.
For calculating head lost due to water flow in the pipe, the general formula (Darcy & Weisbacks formulae) used is
A)
h=4fiv²/2gd
B)
h=i4fiv²/2gd 2ed
C)
h= flv²/2gd
D)
None of these
The Darcy–Weisbach equation for head loss due to friction in a pipe is:
h_f = 4f(L/D)(V^2/2g)
where f is the Darcy friction factor, L is the length of pipe, D is diameter, V is mean velocity, and g is acceleration due to gravity.
Among the given options, option (c) represents this formula (the printed text is slightly distorted), so it is the correct answer.
Why others are incorrect:
- (a) and (b) appear to be misprinted/garbled versions.
- (d) is incorrect because option (c) matches the standard Darcy–Weisbach form.
Cetane number of Diesel oil normally available in market is in the range
A)
45-50
B)
60 - 65
C)
75 - 80
D)
90 - 100
Cetane number indicates the ignition quality of diesel fuel. Diesel oil normally available in the market generally has a cetane number in the range of about 45 to 50. Higher values like 60–65 or above are better-quality fuels, but they are not the usual market range. Therefore, option (a) is correct.
A rotodynamic pump, which does not generate centrifugal force for building up pressure, but pressure is generated by flow of liquids over the blades of aerofoil section just like the lifting action of the wings of an aeroplane, is known as
A)
Axial flow pump
B)
Centrifugal pump
C)
Vertical Turbine pump
D)
None of these
In an axial flow pump, the liquid flows parallel to the axis of the pump. The pressure rise is produced mainly by the lifting action of the aerofoil-shaped blades, similar to the wings of an aeroplane, and not by centrifugal force. A centrifugal pump, on the other hand, builds pressure mainly by centrifugal action. Vertical turbine pump is a type of pump arrangement, not the specific rotodynamic principle described here.
In factories the power or rotary motion from one shaft to another is usually transmitted by means of
A)
Crankshaft
B)
Belts or ropes
C)
HT lines
D)
None of these
In factories, rotary motion and power are commonly transmitted from one shaft to another using belts or ropes. They are simple, economical, and suitable for transmitting motion over some distance. Crankshafts are used to convert reciprocating motion to rotary motion, and HT lines are used for electrical power transmission, not mechanical shaft-to-shaft power transmission.
The maximum permissible variation in the size of the part is
A)
Basic dimensions
B)
Tolerance
C)
Clearance
D)
None of these
The maximum permissible variation in the size of a part from its basic size is called **tolerance**. It defines the allowed upper and lower limits of size during manufacturing.
- **Basic dimension** is the nominal or theoretical size, not the permitted variation.
- **Clearance** is the intentional gap between mating parts, not the variation itself.
- Therefore, the correct answer is **tolerance**.
In forging operation of cutting tools of carbon steel, the operation should be carried out at
A)
850 to 950°C
B)
950 to 1050°C
C)
1050 to 1150°C
D)
None of these
Carbon steel cutting tools are forged in the lower austenitic range to avoid overheating, grain growth, and loss of hardness. For such tools, the recommended forging temperature is about 850 to 950°C. Higher ranges like 950 to 1050°C or 1050 to 1150°C are too hot for carbon steel cutting tools and may damage their properties.
Which transmission unit disengages the drive and provides a smooth take up the drive?
A)
Final drive
B)
Differential
C)
Clutch
D)
Gearbox
The clutch is the transmission unit that temporarily disconnects the engine from the gearbox, thereby disengaging the drive. It also allows the drive to be taken up smoothly when power transmission is restored. The final drive and differential mainly transmit and distribute power to the wheels, while the gearbox changes speed/torque ratios.
The basic philosophy of quality control is
A)
Frequent inspection
B)
Both preventive & remedial
C)
Only preventive
D)
None of these
Quality control is not limited to checking finished output. Its basic philosophy is to prevent defects by controlling the process and also to correct defects when they are found. Therefore, it combines both preventive and remedial actions. Option (a) is too narrow, (c) is incomplete because QC is not only preventive, and (d) is incorrect because option (b) is the right choice.
Which of the following does not form part of belts?
A)
Flat belt
B)
Chain
C)
Belt
D)
V-Belt
Belts in machine elements include flat belts, V-belts, and other belt types used for power transmission. A chain is not a belt; it belongs to chain drive systems. Therefore, the option that does not form part of belts is Chain.
Which of the following is not a type of Boring machine?
A)
Slotting machine
B)
Jigboring machine
C)
Horizontal boring machine
D)
Vertical boring machine
Boring machines are used to enlarge existing holes with high accuracy. Common types include horizontal boring machines, vertical boring machines, and jig boring machines. A slotting machine is a machine tool used for cutting slots, grooves, and keyways using a vertical reciprocating tool; it is not a boring machine.
What is a prime consideration in designing the new plant building?
A)
Material handling
B)
Drawings
C)
Machine loading
D)
Value engineering
In industrial engineering, a prime consideration in designing a new plant building is efficient material handling, because the building layout must support smooth movement of materials, reduce travel distance, and minimize delays and handling cost. Drawings are only a planning document, machine loading is a scheduling concern, and value engineering is a cost-reduction technique rather than the primary design consideration for the building itself.
The power (in horse power) transmitted by a belt drive is (T1 = belt tension in tight side, T2 = belt tension in loose side and V = belt speed)
A)
Power = (T1-T2)V
B)
Power = (T1+T2)V
C)
Power = T1V
D)
None of these
In a belt drive, the effective driving force is the difference between the tight-side tension and the loose-side tension, i.e. (T1 - T2). Power transmitted equals force × velocity, so P = (T1 - T2)V. Hence option (a) is correct. Option (b) uses the sum of tensions, which is not the net driving force, and option (c) ignores the loose-side tension, so both are incorrect.
The ratio of the direct stress to the strain produced is called
A)
Shear modulus
B)
Rigidity
C)
Young’s modulus
D)
None of these
Direct stress divided by the corresponding strain gives the modulus of elasticity in tension or compression, which is called Young’s modulus. Shear modulus relates shear stress to shear strain, and rigidity is another term associated with resistance to shear, not direct stress-strain ratio.
A machine tool that removes metal as the work is fed against a rotating multipoint cutter is
A)
Grinding machine
B)
Boring machine
C)
Gear hobbing machine
D)
Milling machine
In a milling machine, the workpiece is fed against a rotating multipoint cutter, and metal is removed in the form of chips.
Why others are incorrect:
- Grinding machine: uses an abrasive wheel, not a multipoint cutter.
- Boring machine: used to enlarge existing holes with a single-point tool.
- Gear hobbing machine: specifically used for cutting gears with a hob, though it also uses a rotating cutter, the general machine tool described here is the milling machine.
A process of joining similar metals by application of heat with or without application of pressure and addition of filler material is called
A)
Smithing
B)
Forging
C)
Pattern making
D)
Welding
Joining similar metals by applying heat, with or without pressure and with or without filler material, is the definition of welding. Smithing and forging are metal-shaping processes, while pattern making is used in casting to create patterns for molds.
The stresses on the principal planes will be pure normal (tension or compression) and their values are called
A)
Principal stresses
B)
Safe stresses
C)
Shear stresses
D)
None of these
On the principal planes, shear stress is zero and only normal stress acts (tension or compression). These normal stresses are called principal stresses. Safe stresses are allowable design stresses, and shear stresses act on planes where tangential force exists, so they are not correct.