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S.No Question Option A Option B Option C Option D Answer Solution Comments Status Action
1 For a laminar flow through a circular pipe, the kinetic energy correction factor is equal to: 5 3 2 4 c Kinetic energy correction factor (): \(α\)
It is defined as the ratio of kinetic energy/second based on actual velocity to the kinetic energy /second based on average velocity.
\(α=\frac{1}{A}A (\frac{u}{V})^{3}dA\)
Where A = area, V = average velocity, u = local velocity at distance r.
In circular pipe laminar flow \(α=2\)		 Comments Active
2 Admittance of oil between two surfaces having relative motion is called: Viscosity Coalescence Lubrication Turbidity c Lubrication
• It is the admittance of oil between two surfaces having relative motion.
Viscosity
• It is defined as the measure of the resistance of a fluid to gradual deformation by shear or tensile stress. In other words, viscosity describes a fluid's resistance to flow.
• the viscosity is the measure of the friction of fluids. There are two ways to measure a fluid's viscosity as dynamic Viscosity (Absolute Viscosity) and Kinematic Viscosity.
Coalescence
• It is the process by which two or more separate masses of miscible substances seem to "pull" each other together until they make the slightest contact.
Turbidity
• Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air.
• The measurement of turbidity is a key test of water quality.		 Comments Active
3 The property of a fluid which offers resistance to the movement of one layer of fluid over another layer of fluid, is called: Turbidity Specific weight Fluidity Viscosity d Viscosity is the resistance offered by a layer of a fluid to the relative motion of another layer. It is also the resistance offered by a fluid to the movement of any object through it e.g. if we move a ball inside water then we would feel less resistance than if we move it in honey, so we can conclude that honey has more viscosity than water.
When a fluid moves relative to a solid or when two fluids move relative to each other. The property that represents the internal resistance of a fluid to motion (i.e. fluidity) is called as viscosity.
The fluids for which the rate of deformation is proportional to the shear stress are called Newtonian fluids and the linear relationship for a one-dimensional system is shown in the figure. The shear stress () is then expressed as, \(Ï„\)
\(τ=μ\frac{du}{dy};\)
• Where is the shear strain rate and is the dynamic (or absolute) viscosity of the fluid. \(\frac{du}{dy}\) \(μ\)
• The dynamic viscosity has the dimension ML-1T¹ and the unit of kg/m.s or, (N-sec)/m² or Pa-s. A common unit of dynamic viscosity is Poise which is equivalent to 0.1 Pa s.		 Comments Active
4 In a two- dimentional flow, a stream line shall be interpreted as: At the edge, velocity vector is normal to the flow A curve such that velocity vector is always tangential and there is no flow in the direction normal to it They are not contours of an impervious two-dimensional body Flow is constant in the direction normal to the flow b Streamline is an imaginary line or series of imaginary lines in a flow field, such that a tangent to this line at any point at any instant represents the direction of the instantaneous velocity vector at that point. Comments Active
5 The maximum working pressure in a Lancashire boiler is: 24 bar 16 bar 28 bar 30 bar b The maximum working pressure in a Lancashire boiler is 16 bar. It is used where the working pressure and power required are moderate. Its steam production rate is 9000 kg/hr. Its efficiency is from 50% to 70% depending upon the type of fuel used. Comments Active
6 In case of reciprocating compressors, irreversibility is due to which of the following reasons? Due to flow of refrigerant at low velocity Due to pressure rise across valves Due to pressure drop and heat transfer Only due to heat transfer c In a reciprocating compressor, due to fluid friction pressure drops occur and due to finite temperature difference heat transfer also occurs. These are the main reason of internal and external irreversibility in reciprocating compressors. Comments Active
7 In a good steam power plant, the Rankine cycle efficiency is in the range of: 35-45% 15-25% 65-75% 75-85% a In a good steam power plant, the Rankine cycle efficiency varies from 35 to 45 %. Comments Active
8 In a reciprocating compressor, the clearance ratio is generally between: 10% and 30% 8% and 20% 5% and 12% 4% and 10% d Clearance ratio is the ratio of clearance volume to the swept volume. This ratio has value in general between 4% to 10% the clearance volume is that volume which remains in the cylinder after the piston has reached the end of its inward stroke. Comments Active
9 The Morse test is used to determine: Specific power Coulomb loss Friction power Brake power c Morse test:
The Morse test is used for measuring the indicated power of the multi – cylinder engines.
This test measures the indicated power by cutting out the spark plug of the cylinder by keeping the speed of the engine constant.
To understand this test better, suppose break power for a cylinder with the spark plug on is and with spark plug cut is then the indicated power will be \(B.P_{1}\) \(B.P1'\) \(B.P_{1}-B.P1'.\)
It is assumed that pumping and friction losses are the same when the spark plug is cut – off or in operation.
Friction power = Indicated power of cylinder – Break the power of the cylinder.
Indicated power of cylinder = Friction power + Break the power of the cylinder.		 Comments Active
10 Which of the following is a high pressure boiler? Cornish Cochran Lancashire Velox d Velox boiler is a high-pressure, forced circulation water tube boiler.
It operates at very high pressures (up to 100 bar or more) and high steam generation rates.
Designed for fast steam generation, it uses a gas turbine-driven air compressor to force air through the combustion chamber.		 Comments Active
11 When a valve is suddenly closed on a liquid flowing through a long pipe, the pressure wave of high intensity thus generated, is known as: Water hammer Flow hammer Pressure wave Jet hammer a When the water flowing in a long pipe is suddenly brought to rest by closing the valve or by any similar cause, there will be a sudden rise in pressure due to the momentum of the moving water being destroyed.
• This causes a wave of high pressure to be transmitted along the pipe which creates noise known as knocking.
•This phenomenon of the sudden rise in pressure in the pipe is known as water hammer or hammer blow.
• A water hammer is developed in a Penstock.
The magnitude of pressure rise depends upon:
• The speed at which the valve is closed
• Velocity of flow
• Length of pipe
• Elastic properties of pipe material as well as that of the flowing fluid.		 Comments Active
12 In a constant volume process, the reversible moving boundary work associated with closed system (in kJ/kg) is: 0 0.5 1 1.5 a For constant volume process W = ∫PdV Since dV = 0 so W = 0 for constant volume process. For free expansion work done is zero. W = 0. Comments Active
13 As per regulations, boilers should be fitted with ________safety valves. four five three two d Two Safety valves are fitted on boilers as a precaution. Each safety valve is designed in such a way that even if the boiler is firing at full throttle still the safety valve opens and releases the excess pressure and if in case one of the safety valves falters the other safety valve will be there. Comments Active
14 The range of specific speed of a Kaplan or propeller turbine is SI units, is: 51 – 225 250 – 850 30 – 51 8.5 – 30 b  
Flow
Energy
Head
Specific speed
Example
Tangential
Impulse
High
(300 m and above)
Low
(0 – 60 RPM)
Pelton Wheel turbine
Radial
Reaction
Medium
(30 m to 300 m)
Medium
(60 – 300) RPM
Francis turbine
Axial
Reaction
Low
(less than 30 m)
High
(300 – 600) RPM
Propeller
Turbine
(600 - 1000) RPM
Kaplan turbine		 Comments Active
15 In steels, the symbol indicating heat treatable plain carbon steel for springs is: CC CE C CS d In the ISI (Indian Standards Institute) system of steel designation:
The symbol "C" stands for plain carbon steel.
The addition of "S" indicates that it is a spring steel, i.e., heat treatable plain carbon steel used for springs.
Thus, "CS" indicates carbon steel used for springs.		 Comments Active
16 A solid to semi solid dispersion of thickening agent in a liquid lubricant is: Lubricating viscofier Lubricating oil Lubricating solid Lubricating grease d Lubricant grease:
Lubricant grease is a solid to semi solid dispersion of a thickening agent in a liquid lubricant.
Grease normally used under the condition of lubrication for which oil is not suitable or convenient.
Grease is considered to a liquid lubricant gelled by a dispersed solid.
The term dropping point is used to define the temperature at which grease passes to a liquid state through either gross melting or separation of the oil phase.
Electron microscope is an extremely useful tool in the study of grease structure.		 Comments Active
17 The mechanical efficiency of a Pelton wheel is given by: Shaft power/runner power Shaft power/water power Runner power/shaft power Water power/shaft power a  Mechanical efficiency=shaft power/runner power
Hydraulic efficiency=runner power/water power
overall efficiency= shaft power /water power		 Comments Active
18 A graphical method of determining the normal, tangential and resultant stresses on an oblique plan is: Force circle Mohr circle Coulomb circle Stress circle b Mohr circle is a two-dimensional graphical representation (σ as x-axis and τ as y-axis) of the state of stress inside a body. The abscissa and ordinate of each point on the circle are the magnitudes of the normal stress and shear stress components, respectively. Comments Active
19 The mechanical efficiency in a four stroke engine is: BP/IP BP + IP BPIP \(×\) BP – IP a It is a performance parameter that gives the effectiveness of an engine in terms of how much input energy converted into output energy. For an internal combustion engine, it is the ratio between the Brake work done and Indicated work done.
\(Mechanical efficiency=\frac{Brake Horse Power(BHP)}{Indicated Horse Power (IHP)}\)		 Comments Active
20 Air- cycle refrigeration system has which of the following assumptions? Cycle is assumed to be an open – loop Working fluid is a fixed mass All processes within the cycle are irreversible Specific heat of air varies continuously throughout the cycle b In an air-cycle refrigeration system, several simplifying assumptions are made to idealize the system for analysis. These include:
The working fluid is air, which behaves as a perfect (ideal) gas.
The mass of air is fixed (hence a closed cycle is assumed for analysis, even if the real system may exchange air with the environment).
All processes in the cycle are assumed to be internally reversible.
Specific heats (Cp and Cv) are constant, not varying continuously.		 Comments Active
21 Entropy is: Heat change / absolute temperature Heat change / absolute pressure Absolute temperature / heat change Absolute pressure / heat change a Entropy (S) is defined as the measure of randomness or disorder in a system.
In thermodynamics, for a reversible process, the change in entropy is given by:
\(∆S=\frac{Q_{rev}}{T} \)
Where, =heat added reversiblyT = absolute temperature at which the heat is added \(Q_{rev}\)		 Comments Active
22 In a boiler, one or more plates are bent into a cylindrical form and riveted or welded together, this is called: Grate Mountings Refractory Shell d The shell of a boiler consist of one or more steel plates bent into a cylindrical form and riveted or welded together. The shell ends are closed with the endplates. Comments Active
23 A centrifugal pump acts as a reverse of: Pelton turbine Outward radial flow reaction turbine Inward radial flow reaction turbine Reciprocating pump c The centrifugal pump acts as a reverse of an inward radial flow reaction turbine. This means that the flow in centrifugal pumps is in the radial outward direction.
 Comments Active
24 The moment of a force about any point in the ______of force and perpendicular distance between the point and line of action of force. Sum Division Product Subtraction c The moment of a force about any point is defined as the product of the force and the perpendicular distance from the point to the line of action of the force.
Mathematically:
Moment=Force × Perpendicular distance		 Comments Active
25 If the temperature of the heat source is 1990 K, and the sink is 850K, then what is the Carnot efficiency? 37.2% 67.4% 22.7% 57.3% d \(T_{1}=1990K,T_{2}=850K,\)
\(n_{carnot}=1-\frac{T_{2}}{T_{1}}=\frac{1990-850}{1990}=0.57%\)		 Comments Active
26 The degree of freedom of a structure or a locked system is: 0 1 3 2 a The degree of freedom of a structure or a locked system is 0.
A structure or a locked system is fully constrained.
It cannot move in any direction (no translation or rotation).
Therefore, it has zero degrees of freedom.		 Comments Active
27 A transmission dynamometer measures: Indicated power Alternate power Specific power Brake power d Transmission dynamometers are devices used to measure the torque and power output of a transmission system. They are typically used in automotive and industrial applications to test and evaluate the performance of transmissions. Comments Active
28 The sublimation, vaporization and fusion curves for a pure substance meet at a _____as seen in a P-T diagram. Double point Zero point Triple point Mono point c The triple point of a substance is the temperature and pressure at which the three phases (gas, liquid, and solid) of that substance coexist in thermodynamic equilibrium. It is that temperature and pressure at which the sublimation, fusion, and vaporization curves meet. Comments Active
29 The steam flow through a nozzle may be assumed as a/an: Convergent flow Isothermal flow Divergent flow Isentropic flow d An adiabatic flow is a condition where the overall heat transfer interaction across the boundary of the system and surroundings is zero.
• If the system boundary is perfectly insulated with the surrounding then the heat interaction will be zero.
• A nozzle is a steady-state steady-flow device to create a high-velocity fluid stream at the expense of its pressure.
• The nozzle is perfectly insulated so the flow is adiabatic and also there is no moving part so shaft work is also zero.		 Comments Active
30 A portion of water is discharged when the boiler is in operation to blow out mud scale or sediments periodically by a: Safety valve Feed check valve Fusible plug Blow off cock d A blow off cock or valve performs the two functions:-
(i) It may discharge a portion of water when the boiler is in operation to blow out mud scale or sediments periodically.
(ii) It may empty the boiler when necessary for cleaning, inspection and repair.		 Comments Active
31 If the motion of any of the movable links result in the definite motion of the others, the linkage is known as: Locked system Mechanism Structure Superstructure b The way in which the parts of a machine are interconnected and guided to produce a required output motion from a given input motion is known as the mechanism of the machine. Comments Active
32 In the main characteristic curve of a centrifugal pump, the power is proportional to: Cube of speed Square of speed Fourth power of speed Speed a   \(P∝N^{3}D^{5}\)
 Comments Active
33 Coefficient of discharge is equal to: Coefficient of Contraction / Coefficient of Acceleration Coefficient of Contraction / Coefficient of Velocity Coefficient of contraction × Coefficient of velocity Coefficient of contraction × Coefficient of acceleration c Co-efficient of Discharge is defined as the ratio of the actual discharge from an orifice to the theoretical discharge from the orifice. \((C_{d})\)
\(C_{d}=\frac{Q}{Q_{th}}=\frac{Actual velocity×Actual area}{Theoretical velocity×Theoretical area}\)
\(C_{d}=\frac{Actual velocity}{Theoretical velocity}×\frac{Actual area}{Theoretical area}=C_{v}×C_{c}\)
So co-efficient of contraction in terms of Cd and Cv is given as
\(C_{c}=\frac{C_{d}}{C_{v}} i.e. C_{d}=C_{c}×C_{v}\)		 Comments Active
34 How many chlorine atoms does the refrigerant R – 134a contain? One Seven Elight Nil d For R-134a, we have a+1 = 1 i.e. a = 2
b + 1 = 3 i.e. b = 2 and c = 4
It must satisfy this 2a + 2 = b + c + d therefore, we get d = 0
Therefore, we get, Câ‚‚Hâ‚‚F4		 Comments Active
35 The total power developed by combustion of fuel in the combustion chamber is called: Specific power Indicated power Brake power Alternate power b Indicated Power:
It is the power developed inside the engine cylinder.
\(ip=\frac{P_{m}LAN.n}{60} \)
Brake Power:
This is the actual power available at the crankshaft and may be called power output of the engine. It is always less than indicated power.
\(BP=\frac{2Ï€NT}{60}\)
Indicated thermal efficiency:
It is the ratio of IP to fuel power.
\(η_{i}=\frac{ip}{m_{f}×CV}\)
Brake thermal efficiency:
It is the ratio of bp to fuel power.
\(η_{b}=\frac{bp}{m_{f}×CV}\)		 Comments Active
36 A real fluid in which shear stress is proportional to rate of shear strain is: Non Newtonian fluid Ideal solid Ideal fluid Newtonian fluid d Ideal Plastic Fluid
When the shear stress is proportional to the velocity gradient and shear stress is more than the yield value, it is known as the ideal plastic fluid.
Newtonian Fluid
The fluid which obeys Newton’s law of viscosity (shear stress is proportional to the rate of shear strain), is known as a Newtonian fluid.
Non – Newtonian Fluid
The fluid which doesn’t obey Newton’s law of viscosity is known as a Newtonian fluid.
Ideal Fluid
A fluid is said to be ideal when it is incompressible and the non – viscous. It is an imaginary fluid that doesn’t exist in reality.
Real Fluid
All the fluids are real as all the fluids possess viscosity.		 Comments Active
37 Which of the following is a fire tube boiler? Babcock and Wilcox Stirling Yarrow Locomotive boiler d The Locomotive Boiler is horizontal, multi-tubular, natural circulation, internally fired, fire tube boiler. Comments Active
38 The Meta stable aggregate consisting of supersaturated ferrite in which carbon has been finely precipitated in the form of carbides is: ferrite martensite bainite cementite c Bainite:
• Very fine microstructure of ferrite and carbides (Fe3C)
• Properties are like ferrite but with different structures.
• Stronger and more ductile than particles at the same hardness level.
Martensite:
• Hardest, brittle, and least ductile constituent of steel.
• Needle-like structure.
• Solid solution of non-carbide in a - iron.
• It has a body-central tetragonal structure.
Ferrite:
• There are two forms of ferrite i.e., ferrite and - ferrite \(α\) \(δ\)
• -ferrite, is a solid solution of body-centered cubic iron. \(α\)
• It has a maximum solid solubility of 0.022% C at a temperature of 727°C.
• - ferrite is another form that is stable only at very high temperatures and is of no practical significance in engineering. \(δ\)
• Ferrite is relatively soft and ductile
Cementite:
• Cementite, which is 100% iron carbide (Fe3C), has a carbon content of 6.67%.
• It is also called carbide.
• It is a very hard and brittle intermetallic compound and has a significant influence on the properties of steel.		 Comments Active
39 The evaporative cooling system is suitable under: Cold and dry condition Cold and humid condition Moderately hot and humid condition Hot and dry condition d The evaporative cooling system is suitable under hot and dry conditions. evaporative cooling systems are ideal in hot and dry places, i.e., in places where the dry bulb temperature is high and the coincident wet bulb temperature is low. The latent heat of evaporation is taken from the water, air, or both of them. Comments Active
40 The phenomenon of vapour bubble formation, and sudden collapsing of it in a turbine, is called: Priming Bubbling Cavitation Vibration c Cavitation is a destructive phenomenon that occurs when the local pressure in a fluid drops below its vapour pressure, leading to the formation of vapour bubbles. These bubbles are then carried to a region of higher pressure, where they collapse violently, creating shock waves. This can lead to:
Pitting and erosion of turbine blades and pump impellers,
Noise and vibrations,
Reduced efficiency
Potential structural damage to components		 Comments Active
41 ‘The moment of a force about any point is equal to the algebraic sum of moments of its components about that point’ is stated by: Avogadro’s principle Henry’s principle Varignon’s principle Lufkin’s principle c Varignon’s Principle of Moments states that: “The moment of a force about any point is equal to the sum of the moments of its components about the same point.”
This principle is fundamental in statics and helps simplify the analysis of complex force systems by breaking them into components.		 Comments Active
42 Air standard efficiency is also called: Effective efficiency Ideal efficiency Overall efficiency Actual efficiency b Air standard efficiency: To compare the effects of the different cycles, it is of paramount importance that the effects of the calorific value of the fuel are altogether eliminated and this can be achieved by considering air (which is assumed to behave as a perfect gas) as the working substance in the English cylinder.
The efficiency of the engine using air as the working medium is known as an “Air standard efficiency”. This efficiency is often called ideal efficiency.
Relative efficiency: The actual efficiency of a cycle is always less than the air – standard efficiency of the cycle under ideal conditions. This is taken by introducing a new term “Relative efficiency” which is defined as:
\(η_{relative}=\frac{Actual thermal efficiency }{Air standard efficiency }\)		 Comments Active
43 The jet ratio in a Pelton wheel is: Pitch diameter of wheel/diameter of jet Outer diameter of wheel/ diameter of jet Diameter of jet/pitch diameter of wheel Diameter of jet/outer diameter of wheel a It is defined as the ratio of the pitch diameter (D) of the Pelton wheel to the diameter of the jet diameter
\(Jet ratio=\frac{D}{d}\)		 Comments Active
44 A fluid in which shear stress is more than the yield value, and shear stress is proportional to the rate of shear strain, is: Newtonian fluid real fluid ideal fluid ideal plastic fluid d Ideal Plastic Fluid
When the shear stress is proportional to the velocity gradient and shear stress is more than the yield value, it is known as the ideal plastic fluid.
Newtonian Fluid
The fluid which obeys Newton’s law of viscosity (shear stress is proportional to the rate of shear strain), is known as a Newtonian fluid.
Non – Newtonian Fluid
The fluid which doesn’t obey Newton’s law of viscosity is known as a Newtonian fluid.
Ideal Fluid
A fluid is said to be ideal when it is incompressible and the non – viscous. It is an imaginary fluid that doesn’t exist in reality.
Real Fluid
All the fluids are real as all the fluids possess viscosity.		 Comments Active
45 Which of the following is NOT a property of a pure substance? Heterogeneous in chemical aggregation Invariable in chemical aggregation Homogenous in composition Homogenous in chemical aggregation a A pure substance has the same type of particles with fixed melting and boiling point. It has a definite composition and is, therefore, homogeneous in nature. Comments Active
46 Specific internal energy of a perfect gas is a function of: Differential pressure Absolute volume Absolute pressure Absolute temperature d According to joules law states that the internal energy of a given quantity of a gas depends only on the temperature. It is independent of pressure and volume. Comments Active
47 The capacity of a refrigeration system is 10 TR. What is the heat extracted per minute? 1800 kJ/min 2100 kJ/min 2000 kJ/min 1900 kJ/min b Refrigeration capacity (RC) = 10 TR
Heat extracted per minute = 10 TR X 210 kJ/min = 2100 kJ/min		 Comments Active
48 A ____________is a device used for measuring the rate of flow of a fluid flowing through a pipe. Hygrometer Barometer Manometer Venturimeter d A Venturimeter is a device used for measuring the rate of a flow of a fluid flowing through a pipe Comments Active
49 Clearance ratio is: Clearance volume / swept volume Swept volume / clearance volume Clearance volume / total volume Total volume / swept volume a Clearance ratio: It is the ratio of clearance volume to the swept volume C = This ratio has value in general between 4% to 10% Comments Active
50 Which refrigerant is used commonly in domestic refrigerators? Sulphur dioxide Carbon dioxide R – 134a R12 c Domestic refrigerators generally run on the vapor compression cycle. In this cycle, a circulating refrigerant such as R134a enters a compressor as low-pressure vapour at or slightly below the temperature of the refrigerator space.
Ammonia is generally used in the vapour absorption cycle.
Nitrogen and CO2 are not used as refrigerants.		 Comments Active
51 The value of the coefficient of velocity for sharp edged orifice, is: 0.85 0.41 0.66 0.98 d • Coefficient of velocity is defined as the ratio between actual velocity of a jet of liquid at vena-contracta and the theoretical velocity of jet.
• It varies from 0.95 to 0.99 for different orifice, depending on the shape, size of the orifice and on the head under which flow takes place.
• The value of coefficient of velocity is 0.98 for sharp edged orifice.		 Comments Active
52 Which of the following is a secondary refrigerant, when used above 0ᵒC? Water Glysols Brines Sodium chloride a Secondary refrigerants are fluids used to transfer heat from the cooled space to the primary refrigerant. Both water and brines can act as secondary refrigerants, but water freezes at 0°C, so it is only suitable for use above 0°C. Brines (salt solutions) and glycols are used as secondary refrigerants below 0°C due to their lower freezing points. Therefore, water is the correct secondary refrigerant for applications above 0°C. Comments Active
53 Circulating water around the cylinder, which helps the air to cool during compression, is called: Oil jacketing Pack jacketing Flow jacketing Water jacketing d There are two types of cooling systems:
1. Air cooling system
2. Water – cooling system
Now, The main parts in the water – cooling system are:
1. Water pump – This is a centrifugal type pump. It is centrally mounted at the front of the cylinder block and is usually driven by means of a belt.
2. Fan – It is generally mounted on the water pump pulley, although on some engines it is attached directly to the crankshaft.
3. Radiator – The purpose of the radiator is to cool down the water received from the engine.
4. Thermostat Valve – It is a kind of check valve which opens and closes with the effect of temperature.
5. Water Jackets: In this water is circulated around the cylinder to help for cooling the air during compression.		 Comments Active
54 The difference between indicated power and brake power is: Engine power Absolute power Engine friction loss Engine accumulated power c Engine Performance Parameters:
Indicated Power:
It is the power developed inside the engine cylinder.
I.P = \(\frac{p_{m}LANK}{60}\)
Brake Power:
This is the actual power available at the crankshaft and may be called the power output of the engine. It is always less than indicated power.
B P = \(\frac{2Ï€NT}{60}\)
Friction Power:
It is the power loss in overcoming the friction between piston and cylinder walls, between the crankshaft and camshaft and their bearings, etc,
It is the difference between indicated power and Brake power.
F.P = I.P – B P		 Comments Active
55 Specific volume is reciprocal of: Mass density Area Volume Mass a The reciprocal of the mass density is known as Specific volume. The Specific volume of a material is the ratio of the volume of the material to its mass. Specific volume is defined as the number of cubic meters occupied by one kilogram of a substance. The normal unit shall be the cubic meter per kilogram (m3/kg). Comments Active
56 If the Reynolds number in a pipe is less than _____then the flow is said to be laminar. 2500 4000 2000 3000 c Laminar flow:
• A flow is said to be laminar when various fluid particles move in layers or laminae, or well-defined paths, with one layer of fluid, smoothly sliding over an adjacent layer.
Reynolds Number = Inertial Force / Viscous Force
Reynolds number for flow in channels is given as.
\(Re=\frac{ρVD}{μ}\)
Where V is the mean velocity of the flow. is the mass density, µ is the dynamic viscosity and D is known diameter of the pipe. \(ρ\)
The Kind of flow is based on the value of Re:
If Re < 2000, the flow is called laminar
If Re > 4000, the flow is called turbulent
If 2000 < Re < 4000, the flow is called transition.		 Comments Active
57 The differential manometer consists of a tube of __________shape. V U X T b A differential manometer is a device used to measure the difference in pressure between two points in a fluid system. It consists of a U-shaped tube filled with a manometric fluid (like mercury or water).
The U-shape allows the fluid to balance the pressure applied at both ends.
The difference in height of the fluid columns in the two limbs gives the pressure difference.		 Comments Active
58 Change in entropy (in kJ/kg.K) in a reversible adiabatic process is: 0 2 1 1.5 a As we know that in reversible adiabatic process, internal entropy change is always zero. Adiabatic means no transfer of heat. So we can conclude that the entropy and heat change in adiabatic reversible process is zero. Comments Active
59 The number of heat exchangers in a boot strap air cooling system is: four three one two d Boot-strap system: It has two heat exchanges instead of one and the expansion turbine drives a compressor rather than a fan. Comments Active
60 The efficiency of a Cochran boiler is in the range of: 70 – 75% 90 – 95% 20 – 25% 40 – 45% a The efficiency of a Cochran boiler varies in the range of 70 to 75%, it depends on the fuel used. The steam capacity of a Cochran boiler is 3500 kg/hr and working pressure around 6.5 bar. The maximum steam capacity and working pressure are 4000 kg/hr and 15 bar respectively Comments Active
61 In a boiler, the platform in the furnace upon which fuel is burnt and is made of cast iron bars, is the: Shell Mountings Grate Furnace c Grate: It is a Cast Iron platform in the furnace of boiler on which fuel is burnt. Fuel is coal or wood or any other solid fuel which rests on the perforated surface of grate made of C.I. bars. Comments Active
62 The work output from the turbine in case of a Rankine cycle is given by: Temperature change between inlet and outlet Enthalpy change between inlet and outlet Entropy change between inlet and outlet Pressure change between inlet and outlet b The work output from the turbine in the Rankine cycle is given by the change of enthalpy between inlet and outlet.
\(W_{turbine}=h_{1}-h_{2}\)		 Comments Active
63 If the velocity of fluid does NOT change with respect to time, the flow is said to be: Interflow Cross flow Steady flow Non uniform flow c Uniform flow is defined as the type of flow in which the velocity at any given time does not change with respect to space.
\((\frac{∂V}{∂s})_{t=const}=0\)
Non-Uniform Flow is defined as the type of flow in which the velocity at any given time changes with respect to space.
\((\frac{∂V}{∂s})_{t=const}≠0\)
Steady Flow: When the fluid properties do not change with respect to time, then the flow is known as steady flow.
Unsteady flow: When the fluid properties change with respect to time, then the flow is known as unsteady flow.		 Comments Active
64 A ________is an instrument used for measuring small pressures, where accuracy is required. anemometer hygrometer single column inclined manometer ammeter c Inclined column manometer:
In an inclined column manometer the column is inclined at some angle with the horizontal axis.
Due to inclination, the distance moved by the heavy liquid in the right limb is more.
This manometer is more sensitive.

The sensitivity of the inclined manometer is given by \(\frac{1}{sinθ}\)
The inclined manometer is used for measuring the actual airflow and is simply a more sensitive way of using a manometer, what is of interest is still the height the fluid moves up vertically.		 Comments Active
65 When is a perfect vacuum obtained? When both absolute pressure and molecular momentum are zero When gauge pressure is zero When molecular momentum is unity and atmospheric pressure is zero When atmospheric pressure is zero a A perfect vacuum is an ideal condition that cannot be achieved in practice but can be theoretically defined as:
A space completely devoid of matter, where:
Absolute pressure is zero, and
Molecular momentum is zero (i.e., no molecules exist to exert pressure or possess kinetic energy).		 Comments Active
66 Vacuum pressure is: Atmospheric pressure / absolute pressure Atmospheric pressure - absolute pressure Atmospheric pressure × absolute pressure Atmospheric pressure + absolute pressure b Vacuum pressure = Atmospheric pressure – absolute pressure Comments Active
67 The number of flue tubes in a Cornish boiler is: three four one two c Cornish boiler is similar to the Lancashire boiler in all respects, except there is only one flue tube in the Cornish boiler instead of two in the Lancashire boiler, the diameter of the Cornish boiler is generally 1 m to 2 m and its length varies from 5 m to 7.5 m. Comments Active
68 Calculate the dryness fraction of steam which has 1.5 kg of water in suspension with 50 kg of steam. 0.75 0.83 0.68 0.97 d Given:
Mass of vapour=50kg;
Mass of liquid=1.5kg
Dryness fraction of Steam is the ratio of the mass of dry steam to the sum of the mass of dry & wet steam.
\(x=\frac{mass of dry steam}{mass of dry steam+mass of suspended wter}\)
X=50/51.5=0.97		 Comments Active
69 The boiler is protected from damage due to overheating for low water level, using a: Fusible plug Blow off cock Feed check valve Safety valve a The function of fusible plug is to protect the boiler from damage due to overheating of boiler tubes by low water level. It is simply a hollow gun metal plug screwed into the fire box. Comments Active
70 What is the composition of low alloy steel 48XX? Ni=3.5%, Mo=0.25% c=0.06%, Cr=13% C=0.03%, Cr=1.3% C=0.6%, Cr=1.3% a Low alloy steel:
• It is a group of Low carbon alloys generally containing carbon less than 0.25% and also known as high strength, low alloy steel (HSLA).
• Major alloying elements in HSLA is copper, vanadium, nickel, and molybdenum in combined concentrations as high as 10%.
Plain Low carbon steels
• It contains carbon less than 0.25% little manganese and residual concentrations of impurities.
Designation of steel:
• The AISI/SAE designation for the steels is a four-digit number
The first two digits indicate alloy content and the last two-digit give the carbon concentration.
• The carbon concentration is represented as the weight percent of carbon multiplied by 100.
• The AISI/SAE designation of plain carbon steels is 10XX and 11XX. The AISI/SAE designation of alloy steels is from 13XX, 41XX, 43XX, 48XX, 46XX, etc.		 Comments Active
71 Regenerative heating in a steam power cycle: Decrease thermal efficiency Increase and decrease depends on the point of extraction of steam Increases thermal efficiency No effect on thermal efficiency c In the regenerative cycle, a portion of the partially expanded steam is drawn off between the high - and low-pressure turbines. The steam is used to preheat the condensed liquid before it is returned to the boiler. In this way, the amount of heat added at low temperatures is reduced. Hence, regenerative heating improves the performance of steam power plants by increasing thermal efficiency. Comments Active
72 In a reversible adiabatic process, the heat added (in joule) is: 2 1.5 1 0 d A reversible adiabatic process (also called an isentropic process) is characterized by:
Adiabatic: No heat exchange with the surroundings (i.e., Q = 0)
Reversible: The process can be reversed without loss of energy.
So by definition: Heat added (Q) = 0 Joule		 Comments Active
73 Parallel force have their lines of action: Transverse to each other Perpendicular to each other Tangential to each other Parallel to each other d • Like Parallel Forces: The forces, whose lines of action are parallel to each other and all of them act in the same direction as shown in Figure are known as like parallel forces.
• Unlike Parallel Forces: The forces, whose lines of action are parallel to each other and all of them do not act in the same direction as shown in Figure are known as unlike parallel forces.
 Comments Active
74 A cylindrical rod threaded at both the ends is called a: bolt stud rivet allen bolt b A threaded rod, also known as a stud, is a relatively long rod that is threaded on both ends
 Comments Active
75 A ______ is a device used for measuring pressure at a point in a fluid. ammeter thermometer manometer hygrometer c A manometer measures the difference between two different points of pressure.
• A manometer works by balancing the weight of a column of fluid between the two points of interest. So while measuring the pressure in the pipes the manometer is connected at two points and the difference in a liquid column gives the pressure.		 Comments Active
76 If at the inlet, only kinetic energy is available, then name the turbine. Low specific speed turbine Mixed – flow turbine Impulse turbine Reaction turbine c  If the energy available at the inlet of the turbine is only kinetic energy, the turbine so known as impulse turbine. The available energy at the inlet is only kinetic energy if the inlet pressure and outlet pressure is the same equal to atmospheric pressure. Comments Active
77 When a body is subjected to two forces, the body will be in equilibrium if the two forces are: Collinear, equal and act in the same direction Collinear, equal and opposite Non collinear, equal and opposite Collinear, unequal and opposite b Principles of equilibrium
1. Two force principle: If only two forces act on a body that is in equilibrium, then they must be equal in magnitude, co-linear and opposite in sense.

2. Three force principle: If a body in equilibrium is acted upon by three forces, then the resultant of any two forces must be equal, opposite and collinear with the third force. If a three-force member is in equilibrium and the forces are not parallel, they must be concurrent. Therefore, the lines of action of all three forces acting on such a member must intersect at a common point; any single force is, therefore, the equilibrant of the other two forces.		 Comments Active
78 A compound of iron and carbon, called iron carbide, is also known as: Ferrite Martensite Bainite Cementite d • Cast irons typically contain 2-4 wt % of carbon with a high silicon concentration and a greater concentration of impurities than steel. Carbon in cast iron can be present in two forms:
• Free carbon or graphite form
• Chemically combined form
• Carbon is present in the form of graphite in grey cast iron and in the form of combined cementite in white cast iron.
• A high cooling rate and a low carbon equivalent favor the formation of white cast iron whereas a low cooling rate or a high carbon equivalent promotes grey cast iron.
• The higher the percentage of carbon more will be cementite and the harder will be the iron.		 Comments Active
79 In a steam nozzle, the heat energy of steam is converted to: Kinetic energy Potential energy Potential energy – kinetic energy Potential energy + kinetic energy a In a steam nozzle, the thermal (heat) energy of the steam is converted primarily into kinetic energy.
As steam flows through the nozzle, its pressure and temperature drop, and the velocity increases significantly.
This conversion increases the steam's velocity, which is essential for doing work in turbines or other steam engines.
Potential energy (pressure energy) decreases, while kinetic energy rises.
So, the main energy transformation in a steam nozzle is from heat (pressure) energy to kinetic energy.		 Comments Active
80 In high speed compressors, _________bearings are used. Bronze Precision insert Copper Sleeve type b In high-speed compressors, Precision Insert bearings are used. The insert bearings are finished with precision and can be used on the compressor without the necessity of machining, scraping, and finishing after fitting on the compressor. Comments Active
81 HS6-5-2-5 indicates a high speed steel containing: Mo=6%, W=5%, v = 2%, Co =5% Co=6%, Mo=5%, V=2%, W=5% Mo=6%, V=5%, W=2%,Co =5% W=6%, Mo=5%, V=2%, Co=5% d High – speed steel:
These steels are used for cutting metals at a much higher cutting speed than other tool steels.
The high – speed steels have the valuable property of retaining their hardness even when heated to red hot.
High-speed steel is of the following types:
High-speed steel
Composition
Application
Molybdenum high-speed steel
W = 6%, M0 = 5%
V = 2%, C0 = 5%
Drilling
Tapping operations
18 – 4 – 1 high-speed steel
W = 18%, Cr = 4%
V = 1%,
Lathe
Planer and shaper tools
Milling cutters
Cobalt high speed steel
W = 20%, Cr = 4%
V = 2%, C0 =12%
Reamers
Punches		 Comments Active
82 If the fluid mass is moving in a curved path with the help of some external torque, the flow is called. Rotating flow Mixed flow Free vortex flow Forced vortex flow d Forced vortex flow: In this type of vortex flow, some external torque is required to rotate the fluid mass at constant angular velocity about a particular axis.
All fluid particles rotate with same angular velocity like a solid hence forced vortex flow is also known as solid body rotation.
To maintain a forced vortex flow mechanical energy has to be spent from outside and thus an external torque is always necessary.
Bernoulli equation is invalid in a forced vortex flow. That means forced vortex flow is a rotational flow.
As we move away from the centerline, streamline spacing decreases.
= constant \(ω\)
V/r = constant
 Comments Active
83 The ratio of specific heat at constant pressure to the specific heat at constant volume for a triatomic gas is: 1.6 1.3 1.8 1.4 b For an ideal gas,
Cp−Cv=R
The ratio γ=Cp/Cv
Monatomic gases have γ≈1.67 (like helium, argon).
Diatomic gases have γ≈1.4 (like nitrogen, oxygen).
Triatomic gases (like CO₂, H₂O vapor) have more degrees of freedom (rotational and vibrational), so their Cv is higher, making γ (gamma) lower, around 1.3.		 Comments Active
84 When the fluid is at rest, the shear stress in N/m2 is: 0.5 0.25 0 1 c A solid can resist shear stress by a static deformation; a fluid cannot.
Any shear stress applied to a fluid, no matter how small, will result in the motion of that fluid
The fluid moves and deforms continuously as the shear stress is applied
So, a fluid at rest must be in a state of zero shear stress		 Comments Active
85 Air standard Otto cycle consists of: Two constant pressures and two constant entropy processes Two constant volumes and two constant entropy processes Two adiabatic and two isothermal processes Two constant pressures and two constant volume processes b The air – standard – Otto cycle is the idealized cycle for the spark – ignition internal combustion engines.
The Otto cycle 1 – 2 - 3 – 4 consists of following four process:
Process 1 – 2: Reversible adiabatic compression of air
Process 2 – 3: Heat addition at constant volume
Process 3 – 4: Reversible adiabatic expansion of air
Process 4 – 1: Heat rejection at constant volume
 Comments Active
86 The refrigerants belonging to the Freon group are: Azeotrope Inorganic Halocarbon Hydrocarbon c Halocarbon compounds: Contains one or more halogens, chlorine, and bromine.
Application: Domestic, commercial, and industrial purposes.
Azeotropic mixtures: Mixtures of refrigerants which behave as pure substance are known as an azeotropic mixture. For example, R-502.
Inorganic refrigerants: This is the refrigerant which consists of inorganic compounds like ammonia (NH3) and water (H2O).
Hydrocarbon refrigerants: Hydrocarbonare comprised of only hydrogen and carbon atoms. None of the hydrogen atoms have been replaced with chlorine or fluorine. Two common hydrocarbon refrigerants are methane and ethane.		 Comments Active
87 Which of the following is the basic property of fluid? More compact in structure It undergoes a definite deformation Never regain its original shape on release of shear stress Can resist tangential stresses in static condition c Fluids
Solids
Fluids have no shape
Solids have a definite shape
Fluids cannot sustain a shear force, i.e. a fluid is always in motion
Solids can sustain a shear force; i.e. they remain static
Stress is a function of the rate of strain, thus a fluid had a ‘dynamic’ state
Stress is a function of strain, thus a solid maintain a static or ‘quasi-static’ state.
On removal of load, fluid will never try to regain its original position
On removal of load solid will try to regain their original position		 Comments Active
88 What data is required to determine the stability of a floating body? Angle of tilt of the floating body Mass of the floating body Displaced volume of the floating body Position of the metacenter d
• Stable equilibrium: The metacenter is above the centre of gravity of the body, then the disturbing couple is balanced by restoring couple, the body will be in stable equilibrium.
• Unstable equilibrium: The metacenter is below the centre of gravity of the body, then the disturbing couple is supported by restoring couple, the body will be in unstable equilibrium.
• Neutral equilibrium: The metacenter and the centre of gravity coincides at the same point, then the body is in neutral equilibrium.		 Comments Active
89 The upward force equal to the weight of fluid displaced by the body is called: Centre of mass Buoyancy Metacenter Metacentric height b According to Archimedes’ Principle, when a body is partially or fully submerged in a fluid, it experiences an upward force called buoyancy. This buoyant force is equal in magnitude to the weight of the fluid displaced by the body.
This force acts vertically upward through the center of buoyancy, which is the centroid of the displaced fluid volume.
Mathematically written as:
\(F_{b}=ρ×g×V\)
Where the buoyant force, is the density of the fluid, V is the submerged volume, and g is the acceleration due to gravity. \(F_{b}\) \(ρ\)		 Comments Active
90 The cooler placed in between stages of a reciprocating compressor is called: Cross cooler Counter cooler Flow cooler Intercooler d Intercooler: The intercooler is a constant pressure device which cools the working fluid at constant pressure. In a two or multistage air compressor, an intercooler is always placed between the low pressure (L.P.) and high pressure (H.P.) cylinder. Comments Active
91 Vorticity is ________times the value of angular velocity. four two three five b Vorticity is equal to twice of the rotation vector
i.e. \(ξ=2ω\)
But, \(ω=\frac{1}{2}(∇×V)\)
\(ξ=2ω=2.\frac{1}{2}(∇×V)\)
\(ξ=∇×V\)
Where represents velocity field \(V\)
\(V=ui+vj+wk\)		 Comments Active
92 The ratio of specific heat at constant pressure to the specific heat at constant volume for a monoatomic gas is: 1.8 1.4 1.2 1.6 d Specific heat at a constant volume, Cv=3R/2Specific heat at a constant pressure, Cp=5R/2 the ratio of specific heat at constant pressure to the specific heat at constant volume for monoatomic gas is 1.6 Comments Active
93 Nozzle efficiency in a steam turbine is defined as: The ratio of isentropic enthalpy drop to the actual enthalpy drop The ratio of isentropic enthalpy drop to the actual potential drop The ratio of actual potential drop to the isentropic enthalpy drop The ratio of actual enthalpy drop to the isentropic enthalpy drop d Nozzle is a duct that increases the velocity of the flowing fluid at the expense of pressure drop.
Nozzle efficiency can be defined as the ratio of actual enthalpy drop to the isentropic enthalpy drop.		 Comments Active
94 A superstructure has: Infinite degree of freedom Negative degree of freedom Positive degree of freedom No degree of freedom b Degree of Freedom:
The DOF of a mechanism refers to the number of independent parameters required to completely specify the configuration of the mechanism in space.
According to Kutzback’s equation of DOF
DOF = 3(n – 1) – 2j – h
Where, n = Number of links, j = Number of joints, h = Number of higher pairs in mechanism.
The physical interpretation of DOF:
DOF < 0, Over structure/Superstructure
DOF = 0, structure/Frame/Truss
DOF > 0, Mechanism		 Comments Active
95 Losses caused due to leakage of combustion products past the cylinder into the crank case are termed as: Pass by losses Follow by losses Flow by losses Blowby losses d It is the phenomenon of leakage of combustion products (gases) from the cylinder to the crankcase past the piston and piston rings.
It depends upon the compression ratio, inlet pressure and condition of piston rings.
Blowby losses are proportional to the square root of inlet pressure.		 Comments Active
96 Which of the following does NOT come under the forced circulation type of boilers? Lancashire Benson Lamont Velox a According to the method of circulation of the water, boilers are classified
• Natural circulation: If the circulation of water takes place due to the difference in density caused by the temperature of the water, then it is called a natural circulation boiler.
Boiler with the natural circulation of water
Lancashire boiler
Babcock-Wilcox boiler
Cochran boiler
• Forced circulation: If the circulation water takes place with the help of an external pump, then it is called a forced circulation boiler.
Boiler with forced circulation of water
La Mont
Benson
Velox		 Comments Active
97 In a fire tube boiler, the operating pressure range is: 30 to 35 bar 26 to 29 bar 21 to 25 bar 16 to 20 bar d In Fire tube boiler, the hot flue gases are present inside the tubes and water surrounds them and sometimes around the outside of the tubes. Hence we can say that they are internally as well as externally fired boilers. They are low-pressure boilers. The operating pressure is about 15 to 20 bar. Comments Active
98 The value of a laminar Darcy friction factor for viscous flow through a pipe is given by ___________where Re is the Reynolds number. 8/Re 32/Re 64/Re 4/Re c For Laminar Flow
Friction Factor \(f=\frac{64}{R_{e}} and F^{'}=\frac{1}{4}×\frac{64}{R_{e}}=\frac{16}{R_{e}}\)
For Turbulent flow
\(f=\frac{0.316}{Re\frac{1}{4}}\)		 Comments Active
99 Enthalpy is: Internal energy × pressure volume product Internal energy / pressure volume product Internal energy - pressure volume product Internal energy + pressure volume product d  Enthalpy is defined as follows H =U+ PV enthalpy is the sum of the internal energy and product of pressure into volume. Comments Active