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Past Questions — 2016
Wheel base of a vehicle is the
A)
Distance between front & rear axles
B)
Distance between the front tyres
C)
Extreme length of the vehicle
D)
The combined width of rear tyres
Wheel base is defined as the distance between the front axle and the rear axle of a vehicle. Therefore, option (a) is correct. Option (b) refers to front track width, option (c) is overall length, and option (d) is not the definition of wheel base.
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.
The coal is reduced to a fine powder with the help of grinding mill and then projected into the combustion chamber with the help of hot air current is known as
A)
Pulverized fuel firing
B)
Manual fuel firing
C)
Non-Pulverized fuel firing
D)
None of these
In pulverized fuel firing, coal is first ground into a very fine powder in a grinding mill and then blown into the combustion chamber using hot air. This increases the surface area of coal, so it burns rapidly and efficiently. Manual fuel firing involves feeding solid fuel by hand, while non-pulverized fuel firing uses coal without pulverizing it.
A substitute for “one who likes to spend time with others” in one word can be
A)
Introvert
B)
Commoner
C)
Extrovert
D)
Extraordinary
An extrovert is a person who is outgoing, sociable, and enjoys spending time with others.
- Introvert means a person who prefers solitude or limited social interaction.
- Commoner means an ordinary person, not related to personality type.
- Extraordinary means very unusual or remarkable, which is unrelated here.
Therefore, the correct one-word substitute is Extrovert.
Brake lining is mounted on
A)
Brake shoe
B)
Brake drum
C)
Master Cylinder
D)
Wheel Cylinder
Brake lining is the friction material fixed to the brake shoe in drum brakes. When the brake is applied, the brake shoe with its lining presses against the brake drum to create friction and slow the vehicle. The brake drum is the rotating part, while the master cylinder and wheel cylinder are hydraulic components, not the mounting surface for the lining.
What is the machining time to turn a MS. bar of 3cm dia down to 2.5cm for a length of 10cm in a single cut. Assume cutting speed = 30m/min and feed = 0.4mm/rev.
A)
0.79 min
B)
7.9 min
C)
0.079 min
D)
None of these
For turning, machining time = Length of cut / (feed × spindle speed).
Given:
- Initial diameter D = 3 cm = 30 mm
- Cutting speed V = 30 m/min
- Feed f = 0.4 mm/rev
- Length of cut L = 10 cm = 100 mm
Spindle speed:
N = (1000 × V) / (π × D)
= (1000 × 30) / (π × 30)
= 1000 / π
≈ 318.3 rev/min
Machining time:
T = L / (f × N)
= 100 / (0.4 × 318.3)
≈ 100 / 127.32
≈ 0.785 min
≈ 0.79 min
So the correct answer is (a) 0.79 min.
Options (b) and (c) are incorrect because they are too large or too small by about a factor of 10.
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.
Which one is not included in major elements in Air conditioning?
A)
Compressor
B)
Condenser
C)
Evaporator
D)
None of these
In an air-conditioning system, the major elements of the refrigeration cycle include the compressor, condenser, and evaporator (along with the expansion device). Since all three options (a), (b), and (c) are major elements, none of them is excluded. Therefore, the correct answer is (d) None of these.
“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.
The octane rating of petrol commercially available is usually
A)
85-90
B)
90 - 100
C)
100-110
D)
110 - 125
The octane rating of commercially available petrol is usually in the range of about 85 to 90. This is the commonly used fuel grade range for petrol in standard engineering exam context. Options (b), (c), and (d) are too high and correspond to special high-octane or racing-type fuels, not ordinary commercial petrol.
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.
“The law of conservation of energy, according to which the total energy of an isolated system in all its forms remains constant. For a closed system executing a cycle only through heat and work, the change in internal energy is zero”, known as
A)
Second Law of Thermodynamics
B)
Newton’s First Law of Motion
C)
First Law of Thermodynamics
D)
None of these
The statement describes the law of conservation of energy in thermodynamics. It says that energy cannot be created or destroyed, only converted from one form to another. For a closed system undergoing a cycle, the net change in internal energy is zero, which is exactly the First Law of Thermodynamics. The Second Law deals with entropy and direction of heat transfer, and Newton’s First Law is about motion, so both are incorrect.
Which one is not included in one of advantages of gas turbine?
A)
Braking is not effective due to very high speed
B)
Gas turbine is smooth in operation and continuous in performance
C)
It does not have reciprocating parts, hence it is easy to balance. It is free from vibration.
D)
None of these
Gas turbines are known for smooth, continuous operation, absence of reciprocating parts, easy balancing, and very low vibration. These are genuine advantages, so options (b) and (c) are correct advantages. Option (a) is not an advantage of a gas turbine; it is a limitation/undesirable feature related to high speed operation. Therefore, the correct answer is (a).
A type of pump, where a nozzle is placed at the throat of a venturi tube and it discharges either compressed air or steam or water at high velocity. The jet causes suction and water is drawn from suction pipe. The high velocity of mixture is converted into pressure head and the water is raised in the discharge pipe, is known as
A)
Hydraulic ram
B)
Jet Pump
C)
Rotary Pump
D)
None of these
The description matches a **jet pump** (also called an ejector or injector in some contexts). In this pump, a nozzle at the throat of a Venturi tube ejects a high-velocity jet of compressed air, steam, or water. This creates suction that draws water from the suction pipe, and the momentum of the jet-mixed fluid is then converted into pressure head in the discharge pipe.
- **Hydraulic ram** uses the water hammer effect to lift water, so it does not fit.
- **Rotary pump** is a different positive displacement pump type and does not work by jet-induced suction.
- Therefore, the correct answer is **Jet Pump**.
In a centrifugal pump installation, while starting the position of delivery valve is
A)
Fully closed
B)
Fully open
C)
Half open
D)
More than half open
In a centrifugal pump, the delivery valve is kept fully closed while starting. This reduces the load on the motor at start-up because the pump initially develops head but has not yet built up sufficient discharge. After the pump attains normal speed, the delivery valve is opened gradually. If it were open at starting, the motor could be overloaded.
Refrigerant usually used in refrigeration in aeroplane
A)
CO₂
B)
Air
C)
Freon
D)
None of these
In aircraft refrigeration systems, air is usually used as the refrigerant because it is readily available, light in weight, and safe for use in aeroplanes. This is the basis of the air-cycle refrigeration system commonly employed in aircraft. CO₂ and Freon are not the usual refrigerants for aeroplane refrigeration in standard exam context.
Mark the one alternative that is nearest in meaning to the word - Nullity
A)
Impress
B)
No effect
C)
Seclude
D)
Astound
The word 'nullity' means something that is void, invalid, or without legal force; in general usage it can mean something of no value or no effect. Among the options, 'No effect' is the nearest in meaning. The other options—'Impress', 'Seclude', and 'Astound'—are unrelated to the meaning of nullity.
Which part is not common between the SI engine and CI engines?
A)
Fuel Injector
B)
Air Cleaner
C)
Battery
D)
Exhaust Silencer
In an SI (spark ignition) engine, fuel is generally supplied by a carburettor or fuel injection system, while in a CI (compression ignition) engine a fuel injector is essential to inject fuel directly into the cylinder at high pressure. Air cleaner and exhaust silencer are common parts in both engines, and battery is also commonly used in starting/ignition systems. Therefore, the part not common between SI and CI engines is the fuel injector.
A four-cylinder engine has a capacity of 2.4 litres. The swept volume of one cylinder is
A)
2400 cm³
B)
600 cm³
C)
1200 cm³
D)
400 cm³
The total engine capacity is 2.4 litres = 2400 cm³. For a four-cylinder engine, swept volume per cylinder = 2400 ÷ 4 = 600 cm³. Hence, option (b) is correct. The other options are incorrect because they do not equal one-fourth of the total capacity.
A process, which can be reversed bringing both the state of the system and the surroundings to the initial condition without any other inputs is
A)
Irreversible process
B)
Reversible process
C)
Constant process
D)
None of these
A reversible process is one that can be reversed so that both the system and the surroundings return exactly to their initial states without any net change. This matches the definition given in the question. An irreversible process cannot be exactly reversed. 'Constant process' is not a standard thermodynamic classification here.
A process, which can be reversed, cannot lead to the initial state of the system and the surroundings without external inputs, is
A)
Irreversible process
B)
Reversible process
C)
Constant process
D)
None of these
A reversible process can return both the system and surroundings exactly to their initial states by an infinitesimal change, without leaving any net change. If a process cannot restore the initial state of the system and surroundings without external input, it is an irreversible process. Hence, option (a) is correct. Options (b) is opposite in meaning, and (c) is not a standard thermodynamics term for this definition.
The firing order in case of four cylinder in-line engine is usually
A)
1-2-4-3
B)
1-3-4-2
C)
1-4-3-2
D)
Either (b) or (c)
In a four-cylinder in-line engine, the usual firing orders are 1-3-4-2 or 1-4-3-2, depending on the engine design and crank arrangement. Both are commonly used to obtain better balance and smooth running. Therefore, the correct choice is 'Either (b) or (c)'. Options (a) 1-2-4-3 is not the usual firing order for a four-cylinder in-line engine.
Air vessel in a reciprocating pump are fitted to
A)
Increase delivery head
B)
Reduce suction head
C)
Smoothen delivery head
D)
Reduce acceleration head
An air vessel in a reciprocating pump is used to reduce the fluctuations in flow and pressure caused by the reciprocating motion of the piston. By storing and releasing water during the cycle, it helps reduce the acceleration head and also minimizes friction losses. Hence, the correct option is (d). Options (a) and (b) are not the purpose of an air vessel, and (c) is a broader effect, but the standard specific answer is reduction of acceleration head.
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).
A prime mover in which gradual changes in the momentum of a fluid are utilised to produce rotation of a mobile member is
A)
Electric Motor
B)
Turbine
C)
Diesel Engine
D)
None of these
A turbine is a fluid machine in which the gradual change in momentum of a moving fluid is used to produce rotation of a rotor or mobile member. The fluid exerts force on the blades, causing shaft rotation. An electric motor and a diesel engine are not fluid machines of this type, so they are incorrect.