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Past Questions — 2016
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 is one that can be reversed at any stage, and both the system and surroundings can be restored to their initial states with no net change. The question states a process that cannot return the system and surroundings to the initial state without external input, which is the definition of an irreversible process. Hence, option (a) is correct. Option (b) is wrong because reversible processes are fully reversible. Option (c) is not a thermodynamic term here, and (d) is incorrect because (a) fits the statement.
Mark the one alternative that is nearest in meaning to the word - Nullify
A)
Impress
B)
No effect
C)
Seclude
D)
Astound
“Nullify” means to make something invalid, cancel it out, or have no effect. Among the given options, “No effect” is the nearest in meaning. The other options are unrelated: “Impress” means influence favorably, “Seclude” means isolate, and “Astound” means surprise greatly.
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 leaving any net change elsewhere. This matches the definition given in the question. An irreversible process cannot be fully reversed without residual changes, so option (a) is wrong. 'Constant process' is not a standard thermodynamics term for this definition, so option (c) is incorrect. Hence, the correct answer is (b) Reversible process.
IC engine includes
A)
Diesel engine
B)
Petrol engine
C)
Spark Ignition engine
D)
Any of these
An IC (internal combustion) engine is any engine in which combustion of fuel takes place inside the engine cylinder or combustion chamber. Diesel engine, petrol engine, and spark ignition (SI) engine are all types of IC engines. Therefore, the correct choice is 'Any of these'.
Which one is not the method of cooling an I.C. engine?
A)
Air cooling
B)
Oil cooling
C)
Water cooling
D)
Steam cooling
I.C. engines are commonly cooled by air cooling, water cooling, and sometimes oil cooling. Steam cooling is not used as a standard method of cooling in I.C. engines. Therefore, the correct answer is Steam cooling.
In a four-stroke engine, each cylinder has
A)
One valve
B)
Two valves
C)
Three valves
D)
Four valves
In a basic four-stroke engine, each cylinder generally has two valves: one inlet valve and one exhaust valve. The inlet valve admits the air-fuel mixture (or air in diesel engines), and the exhaust valve removes the burnt gases. Hence, the correct answer is Two valves. The other options are not the standard basic configuration.
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. Diesel engines work on the Diesel cycle, while the Dual cycle is a combination of Otto and Diesel characteristics and is not the standard cycle for petrol engines. Therefore, the correct answer is Otto cycle.
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. Here, = (800 + 100) / 100 = 900 / 100 = 9:1. So the correct calculated value is 9:1, which corresponds to option (b).
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 real advantages, matching options (b) and (c). Option (a) is not an advantage of gas turbines; in fact, ineffective braking due to high speed is a limitation, not a benefit. Therefore, the correct answer is (a).
The principle of a radiator of an engine cooling system is to
A)
Act as a reservoir for the water
B)
Cause heat flow by convection currents
C)
Spread out the hot water over a large area
D)
Increase the air speed as it flows over the hot surface
A radiator removes heat from the engine coolant by exposing the hot water/coolant to a large surface area so that heat can be transferred to the surrounding air. This is the basic principle of a radiator. Option (a) describes a header tank/reservoir, not the main cooling principle. Option (b) is incomplete because convection helps, but the radiator’s key principle is increasing heat transfer area. Option (d) refers to the effect of a fan or air flow, not the radiator itself.
The octane rating of petrol commercially available is usually
A)
85-90
B)
90-100
C)
100-110
D)
110 - 125
The octane number of commercially available petrol is usually in the range of about 85 to 90. This reflects its anti-knock quality for spark-ignition engines. Options (b), (c), and (d) are too high for ordinary commercial petrol; such values correspond to premium or highly specialized fuels, not the usual retail petrol grade.
One effect of a punctured carburettor float is
A)
Weak mixture
B)
Low petrol level
C)
High air fuel mixture
D)
Petrol flooding
A carburettor float is meant to maintain a constant fuel level in the float chamber. If the float gets punctured, it fills with petrol, becomes heavier, and fails to rise properly to close the inlet needle valve. As a result, excess petrol keeps entering the carburettor, causing flooding. The other options do not describe the direct effect of a punctured float.
As applied to steering, the abbreviation P.A.S. stands for
A)
Pump assisted system
B)
Pump aided steering
C)
Power activated system
D)
Power assisted steering
In automobile engineering, P.A.S. in the context of steering means Power Assisted Steering, which is a steering system that reduces driver effort by using hydraulic or electric assistance. The other options are not the standard expansion of P.A.S.
“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 conservation of energy and says that for a closed system undergoing a cycle, the change in internal energy is zero. This is exactly the First Law of Thermodynamics. The Second Law deals with direction of heat flow and entropy, while Newton’s First Law is about inertia, not thermodynamic energy conservation.
Indirect Expenses is known as overhead charges, on-cost, burden or indirect charges. Which one is not included in classification of Indirect Expenses?
A)
Factory expenses
B)
Administration & Selling expenses
C)
Distribution expenses
D)
None of these
Indirect expenses (overheads) are commonly classified into factory/workshop expenses, administration expenses, selling expenses, and distribution expenses. Since all the options in (a), (b), and (c) are valid classes of indirect expenses, none of them is excluded. Therefore, the correct answer is (d) None of these.
The unit of power is
A)
Pound
B)
Km
C)
N-m/s
D)
Kg
Power is the rate of doing work. Since work = force × distance, its SI unit is joule, and 1 joule per second (J/s) is the unit of power. Also, 1 J = 1 N·m, so power = N·m/s. The other options are units of mass (kg), length (km), and pound, not power.
For calculating head lost due to water flow in the pipe, the general formula (Darcy & Weisbacks formulae) used is
A)
h=4flv²/2gd
B)
h=14flv²/2gd
C)
h=flv²/2gd
D)
None of these
The Darcy-Weisbach formula for head loss due to friction in a pipe is commonly written as h_f = 4fLv² / (2gD) when f denotes the coefficient of friction in the Fanning form used in many exam texts. Here, L is pipe length, v is mean velocity, g is acceleration due to gravity, and d (or D) is pipe diameter. Option (a) matches this standard form. Option (c) omits the factor 4, and option (b) is not a correct formula.
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. Commercial diesel normally available in the market has a cetane number in the range of about 45 to 50. Higher values mean better ignition quality, but extremely high values like 75–100 are not typical for ordinary diesel fuel.
The resultant upward thrust experienced by a body when immersed in the fluid is known as
A)
Equilibrium of floating bodies
B)
Buoyancy
C)
Weight ofa body
D)
None of these
The upward force exerted by a fluid on a body immersed in it is called buoyancy or buoyant force. This is the resultant upward thrust mentioned in the question. Option (a) is a condition related to floating bodies, (c) is unrelated, and (d) is incorrect because the correct term is given in (b).
Which one is not components of cost?
A)
Prime cost
B)
Factory cost & Office cost
C)
Total cost
D)
None of these
In cost accounting, the main components of cost are prime cost, factory/works cost, office cost, and total cost. Since all options (a), (b), and (c) are components of cost, the correct choice for 'which one is not components of cost' is 'None of these'.
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 light, safe, readily available, and suitable for the air cycle refrigeration used in aeroplanes. CO₂ and Freon are not the usual refrigerants for aircraft cabin cooling. Therefore, the correct answer is Air.
A property used to measure the quality of energy or irreversibility of the process is called
A)
Entropy
B)
Endurance limit
C)
Embossing
D)
None of these
Entropy is the thermodynamic property used to measure the quality of energy and the degree of irreversibility in a process. In the second law of thermodynamics, an increase in entropy indicates irreversibility. The other options are unrelated: endurance limit is a fatigue property of materials, and embossing is a manufacturing process.
At the first sight a petrol engine is identified by
A)
Cylinder size
B)
Power output
C)
Operating speed
D)
Spark plug
A petrol (spark-ignition) engine is identified at first sight by the presence of a spark plug in the cylinder head, which is used to ignite the air-fuel mixture. Diesel engines do not use spark plugs; they use compression ignition. Cylinder size, power output, and operating speed are not distinctive visual identifiers of a petrol engine.
A closed vessel made of high quality steel in which stream is generated from water by the application of heat, is known as
A)
Steam nozzle
B)
Steam Generator (or) a boiler
C)
Steam Jet Draught
D)
None of these
A closed vessel made of high-quality steel in which steam is generated from water by the application of heat is called a boiler, also known as a steam generator.
- Option (a) Steam nozzle: used to convert pressure energy of steam into kinetic energy, not to generate steam.
- Option (c) Steam Jet Draught: a draught-producing device in boilers, not the boiler itself.
- Option (d) None of these: incorrect because the definition matches a boiler.
The base of 1m high column of water will have a pressure of
A)
Zero Kg/cm²
B)
0.1 Kg/cm²
C)
1.0Kg/cm²
D)
10Kg/cm²
Pressure due to a liquid column is given by p = \u03c1gh. For water, a 1 m column produces a pressure of about 9.81 kPa, which is approximately 0.1 kg/cm². Hence the correct answer is 0.1 Kg/cm². The other options are incorrect because 0 pressure is impossible at the base of a water column, while 1.0 and 10 Kg/cm² are much larger than the pressure produced by only 1 m of water.