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S.No Question Option A Option B Option C Option D Answer Solution Comments Status Action
1 If the by-pass factor is 0.30, what will be the efficiency of cooling coil or the contact factor? 0.30 0.15 0.66 0.70 d B.P.F = 0.30
We know
\(η=1-B.P.F\)
= 1 – 0.30
\(η=0.70\)		 Comments Active
2 In a laminar flow of a liquid down an inclined plane, the surface velocity is found to be 60 cm/s. The average velocity of the flow is cm/s is: 15 120 40 30 c For parallel plates:
\(V_{avg}=\frac{2}{3}×V_{max}\)
is the maximum velocity or surface velocity. \(V_{max}\)
\(V_{max}=60cm/s.\)
\(V_{avg}=\frac{2}{3}×V_{max}\)
\(V_{avg}=\frac{2}{3}×60\)
\(V_{avg}=40 cm/s.\)		 Comments Active
3 Pelton wheel is a/an: Inward flow radial turbine Outward flow radial turbine Radial flow impulse turbine Tangential flow impulse turbine d  
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
4 In a refrigeration system, why is receiver installed in the liquid line? To collect the refrigerant To wet the refrigerant To heat the refrigerant To dry the refrigerant a Receiver is a storage vessel designed to hold excess refrigerant which is not in circulation. Refrigeration systems exposed to varying heat loads, or systems utilizing a condenser flooding valve to maintain a minimum head pressure during low ambient temperatures will need a receiver to store excess refrigerant. Comments Active
5 The pressure ratio of a gas power plant cycle corresponding to maximum work output for the given temperature limits of and will be: \(T_{min}\) \(T_{max}\) \((\frac{T_{max}}{T_{min }})^{γ-1/γ}\) \((\frac{T_{max}}{T_{min}})^{γ/2(γ-1)}\) \((\frac{T_{max}}{T_{min}})^{γ/γ-1}\) \((\frac{T_{min}}{T_{max}})^{γ/2(γ-1)}\) b The pressure ratio of a gas power plant cycle corresponding to maximum work output for the given temperature limits of Tmin and Tmax will be \((\frac{T_{max}}{T_{min}})^{γ/2(γ-1)}\) Comments Active
6 If a stream function satisfies the Laplace equation, it is a possible case of fluid flow which is Turbulent Irrotational Rotational Unsteady b Stream Function: It is defined as the scalar function of space and time, such that its partial derivative with respect to any direction gives the velocity component at right angles to that direction.
It is denoted by ψ and defined only for two-dimensional flow.
\(v=\frac{∂ψ}{∂x};u=-\frac{∂ψ}{∂y}\)
Properties of Stream function: If stream function exists, it is a possible case of fluid flow (satisfies continuity equation) which may be rotational or irrotational
• If the stream function satisfies the Laplace equation i.e.
It is a case of irrotational flow. \(\frac{∂^{2}ψ}{∂x^{2}}+\frac{∂^{2}ψ}{∂y^{2}}=0\)
Velocity Potential Function: It is defined as the scalar function of space and time, such that its negative derivative with respect to any direction gives the velocity in that direction.
It is denoted by o and defined for two-dimensional as well as three- dimensional flow.
\(u=-\frac{∂∅}{∂x};v=-\frac{∂∅}{∂y};w=-\frac{∂∅}{∂z}\)
Properties of Velocity Potential function: If velocity potential function exists, the flow should be irrotational
• If the velocity potential function satisfies the Laplace equation i.e.
, it is a case of steady incompressible irrotational flow \(\frac{∂^{2}ψ}{∂x^{2}}+\frac{∂^{2}ψ}{∂y^{2}}=0\)		 Comments Active
7 The internal and external diameters of the impeller of a centrifugal pump are 200 mm and 400 mm, respectively. The pump is running at 1200 rpm. Find the velocity of flow if the vane angle at inlet is 20áµ’. 7.42 m/s 6.67 m/s 3.34 m/s 4.57 m/s d N = 1200 rpm, D1 = 200 mm = 0.2 m. D2 = 250 mm = 0.25 m
Tangential velocity at inlet u1 = \(\frac{Ï€D_{1}N}{60}\)
\(=\frac{π×0.2×1200}{60}=12.56 m/sec\)
Vane angle (tan ) = \(θ\) \(\frac{V_{f}_{1}}{u_{1}}⇒V_{f_{1}}=tan20°×12.56\)
\(V_{f_{1}}=4.57 m/sec.\)		 Comments Active
8 The pitch value in the specification Tr 40 × 14 (P7) of multiple start trapezoidal thread is: 7 mm 14 mm 40 mm 2 mm a ISO Designation of trapezoidal threads:
Tr 40 x 14 (P7):
• Multiple start trapezoidal threads are designated by letter 'Tr'
• Followed by the nominal diameter and the lead separated by sign x
Nominal diameter = 40 mm
Lead 14 mm
• The letter P followed by the pitch expressed in mm.
Pitch = depth/2 = 14/2 = 7 mm		 Comments Active
9 Which of the following statement is INCORRECT with respect to a reheat cycle? Steam rate increases Net work done increases Turbine work increases Work ratio increases a
• Steam, after expansion from the high-pressure turbine, is sent again to the boiler and heated till it reaches superheated condition. It is then left to expand in the low-pressure turbine to attain condenser pressure. The reheat cycle has been developed to take advantage of the increased efficiency with higher pressures, and yet avoid excessive moisture in the low-pressure stages of the turbine.
• With reheat the mean temperature of heat addition Tm increases and so efficiency and work output increases but the steam rate decreases.		 Comments Active
10 Which of the following factors are improved in a gas turbine in the presence of a heat and reheater? Both the thermal efficiency and thermal power output Only the specific power output Only the thermal efficiency Neither the thermal efficiency nor specific power output a Heat Exchanger (Regenerator): Recovers waste heat from turbine exhaust to preheat the air before combustion.
Reduces fuel consumption → improves thermal efficiency.
Reheater: Increases the turbine work output by reheating the working fluid between turbine stages.
This increases the specific work output (network per unit mass flow rate).
Combined Effect:
Thermal Efficiency ↑ (due to regeneration),
Specific Power Output ↑ (due to reheating).		 Comments Active
11 For the same compression ratio and heat rejection, which of the following is true? \((η_{th})Diesel <(η_{th})Duel<(η_{th})Otto\) \((η_{th})Otto <(η_{th})Duel<(η_{th})Diesel\) \((η_{th})Diesel >(η_{th})Duel>(η_{th})Otto\) \((η_{th})Otto >(η_{th})Duel>(η_{th})Diesel\) d
For the same compression ratio and heat rejection, heat supplied is more in Otto cycle and hence it will be more efficient that Diesel and Dual will be in between these two.
Hence \(η_{otto}>η_{dual}>η_{Diesel}\)		 Comments Active
12 The right limb of a simple U- tube manometer containing mercury is open to the atmosphere. The left limb is connected to a pipe in which fluid of specific gravity 0.9 is flowing. The centre of the pipe is 12 cm below the level of mercury in the right limb. Find the pressure of fluid in the pipe if the difference of mercury level in the two limbs is 20 cm. 2.59 N/cm2 3.65 N/cm2 6.22 N/cm2 4.78 N/cm2 a \(For fluid:S_{1}=0.9, ρ_{1}=0.9×1000=900kg/m^{3}\)
For mercury: \(S_{2}=13.6,ρ_{2}=13.6×1000=13600 kg/m^{3}\)

Equating the pressure above A – A:
\(P_{pipe}+P_{left limb}=P_{Right limb}\)
\(P_{pipe}+ρ_{1}gh_{1}=ρ_{2}gh_{2}\)
\(P_{pipe}+900×9.81×0.08=13600×9.81×0.20\)
\(P_{pipe}=25976.88 N/m^{2}=2.597 N/cm^{2}\)		 Comments Active
13 18 – 4 – 1 high steel consists of: 18% W, 4% Ni, 1% Cr 18% W, 4% Cr, 1% V 18%W, 4%V, 1% Cr 18% Cr, 4% V, 1% Cr b High – speed steel is special alloy steel which is obtained by alloying tungsten, Chromium, Vanadium, Cobalt and molybdenum with steel
• HSS is an alloy of 18% tungsten, 4% chromium and 2% Vanadium
• Stellite is an alloy of 30% chromium, 20% tungsten and 1 to 4% carbon and the remaining consists of cobalt		 Comments Active
14 In spur gears, the circle on which the involute is generated is called: Pitch circle Addendum circle Clearance angle Base circle d In spur gears, the circle on which the involute is generated is called the base circle. Comments Active
15 Select the option that correctly matches the items given in List I to those given in List II.
List - I
List – II		 A – 4, B – 2, C – 3, D – 1 A – 3, B – 4, C – 2, D – 1 A – 3, B – 2, C – 4, D – 1 A – 1, B – 2, C – 4, D – 3 c Force balance: Use for calibration of pressure measuring instruments
Barometer: Atmospheric pressure is measured by a device called a barometer; thus, the atmospheric pressure is often referred to as the barometric pressure.
\(P_{atm}=ρgh\)
Mechanical gauge: It is a device used for measuring the gauge pressure by balancing the spring balance or dead weight. The commonly use mechanical pressure gauges are,
• Diaphragm pressure gauge
• Bourdon pressure gauge
• Deadweight pressure gauge
• Bellows pressure gauge
Differential manometer: It is the device used for the difference of pressure between two points in a pipe or two different pipes. The most common type of differential manometer is,
1. U-tube differential manometer
2. Inverted U-tube differential manometer		 Comments Active
16 What is the maximum moisture content in a steam turbine exhaust? 15% 25% 30% 20% a From the consideration of the erosion of blades in the later stages of a turbine, the maximum moisture content at the turbine exhaust is not allowed to exceed 12 %, or the quality of steam to fall below 88 %. Comments Active
17 If any substance is cooled below its triple point pressure, vapour become solid and the process is known as: ablimation vaporization sublimation saturation a Triple point: The temperature and pressure at which the solid, liquid, and vapor phase of a pure substance coexists in equilibrium are called the triple point.
Below the triple point on cooling the vapour directly converts to solid and that process is known as ablimation		 Comments Active
18 A Carnot engine receiving heat at 400 K has an efficiency of 50%. What is the COP of a Carnot refrigerator working between the same temperature limits? 2 3 4 1 d Given:
\(T_{1}=400K,\)
\(n_{carnot}=0.50,\)
\( Cop_{HP}=\frac{1}{n_{carnot} }\)
\(=\frac{1}{0.50}=2 ,\)
\( Cop_{refrigerator}=Cop_{HP}-1=2-1=1 \)		 Comments Active
19 The gas refrigeration cycle is preferred in aircraft refrigeration because of: Low weight per ton Low cost High COP High weight per ton a In aircraft weight is the primary concern. So for aircraft, a refrigeration system which can provide more cooling with low weight is required That's why in aircraft gas refrigeration systems are employed. Comments Active
20 Which of the following devices is used for preheating the air before it is supplied to the boiler? Steam trap Superheater Economiser Injector c An economiser is a mechanical device that reduces energy consumption. It does this by acting as a heat exchanger, preheating the fluids that enter a boiler or recovering residual heat from the combustion products. Comments Active
21 Consider the turbulent flow of a fluid through a circular pipe. Which of the following statements holds true?
I. The fluid is unmixed
II. The fluid is well mixed
III. Re < 4000
IV. Re > 4000		 Only statement IV Only statement I and III Only statements I and IV Only statements II and IV d For Re= 2000- 4000 flow will be transitional hence some intermixing of fluid particle will be there.
For Re> 4000 flow will be purely turbulent hence fluid particle will be well mixed.		 Comments Active
22 What is the work done for a constant volume process? 0.5 -1 1 0 d The work done is the area under the curve for the process. Because there is no area under the curve in a constant-volume process the work done by the gas is zero Comments Active
23 An open tank contains water up to a depth of 2 m and above it an oil of specific gravity 0.9 for a depth of 1 m. Find the pressure intensity at the interface of the two liquids. 9829 N/m2 6829 N/m2 8829 N/m2 7829 N/m2 c \(S_{oil}=0.9, ρ_{oil}=900 kg/m^{3}, h_{oil}=1m, h_{water}=2m\)
\(P=ρ_{oil}×g×h_{oil}\)
\(∴0.9×1000×9.81×1=8829 N/m^{2}\)		 Comments Active
24 If Poisson’s ratio of an elastic material is 0.4, then what will be the ratio of modulus of rigidity to Young’s modulus? 0.86 0.06 0.36 0.16 c 0.357 \(E=2G(1+μ)=\frac{G}{E}=\frac{1}{2(1+0.4)}= \) Comments Active
25 For a forced vortex flow in an open tank, which of the following statements is correct? Fall of liquid level at the centre = 0.5 × rise of liquid level at the ends Fall of liquid level at the centre = rise of liquid level at the ends Fall of liquid level at the centre = 0.95 × rise of liquid level at the ends Fall of liquid level at the centre = 0.98 × rise of liquid level at the ends b Forced vortex motion: To maintain a forced vortex flow, it required a continuous supply of energy or external torque.
• All fluid particles rotate at the constant angular velocity was a solid body. Therefore, a flow of forced vortex is called as a solid body rotation.
• Tangential velocity is directly proportional to the radius.
• v=rw, Where, w = Angular velocity, r = Radius of fluid particle from the axis of rotation.
• The surface profile of vortex flow is parabolic.
• In forced vortex total energy per unit weight increases with an increase in radius. Forced vortex is not irrotational; rather it is a rotational flow with constant vorticity 2w.
• Examples for forced vortex flow is rotating a vessel containing a liquid with constant angular velocity, flow inside the centrifugal pump.
• If there is no spillage then according to the conservation of volume.
• Rise of liquid level at the ends is equal to the fall of liquid level at the center i.e. Z/2 = Z/2		 Comments Active
26 The function of a capillary tube in the refrigeration cycle is to: Control flow Improve COP Produce effect of cooling Reduce component weight a The basic functions of an expansion device used in refrigeration systems are to:
1. Reduce pressure from condenser pressure to evaporator pressure, and
2. Regulate or control the refrigerant flow from the high-pressure liquid line into the evaporator at a rate equal to the evaporation rate in the evaporator.		 Comments Active
27 The overall efficiency of a centrifugal pump is: Ratio of mechanical efficiency to manometric efficiency Product of manometric and hydraulic efficiencies Ratio of manometric efficiency to mechanical efficiency Product of manometric and mechanical efficiencies d overall efficiency= water power / shaft power = \(wQH/P\)
η= ηmanometric X ηmech		 Comments Active
28 Name the point about which a body starts oscillating when a body, floating in a liquid, is tilted even by a small angle. Shear center Center of buoyancy Metacentre Center of gravity c Meta Centre is defined as the point about which a body starts oscillating when the body is tilted by a small angle. The meta-center may also be defined as the point at which the line of action of the force of buoyancy will meet the normal axis of the body when the body is given a small angular displacement. Comments Active
29 Which of the following is NOT an assumption of Bernoulli’s equation? Flow is compressible Flow is irrotational Flow is steady Flow is ideal a The following assumption is made in deriving Bernoulli's equation
1. Flow is steady
2. Fluid is incompressible
3. Fluid is non-viscous (inviscid)
4. The equation is applicable along a streamline
5. Effect of friction is neglected
6. Only pressure and gravity forces are taken into account
7. Velocity is uniform over the cross-section
Note: Bernoulli Equation is given by,
\(\frac{P}{ρg}+\frac{v^{2}}{2g}+Z=Constant\)
 Comments Active
30 Fusible plugs in boilers are made of: Titanium Brass Cast iron Steel b Fusible plug is fitted to the fire box. It is generally made up of brass. Its object is to put off the fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit and avoids the explosion which may takes place due to overheating of the furnace. Comments Active
31 Which of the following is determined by deploying multiple gauge glasses in boilers? Pressure Flow Level Velocity c Gauge Glass (also called water level indicator) is a critical safety device in steam boilers. It is a water level indicator used in steam boilers to view the level of water in the boiler by the operator. A gauge glass shows the current level of water in the boiler, regardless of the boiler's operating conditions. Comments Active
32 Energy of a system is defined as: Path function and intensive property Path function and extensive property Point function and extensive property Point function and intensive property c Point function: The thermodynamic properties which depend on the end state only (independent of the path followed) are known as point function like temperature, pressure, density, volume, enthalpy, entropy. Comments Active
33 In a non-flow process, work transfer from the system is 30 kJ and heat received by the system is 90 kJ. Determine the change in the internal energy. – 60 kJ 80 kJ 60 kJ – 80 kJ c given:
\( ∂W=30KJ, \)
\(∂Q=90KJ, \)
\(∂Q=∆U+∂W, \)
\(∆U=90-30=60KJ.\)		 Comments Active
34 An alloy of nickel and iron that is easily magnetized and demagnetized and can also be used in electrical equipment is: permalloy cunife supermalloy Alnico a Permalloy is an alloy of nickel and iron (80% nickel and 20% iron content) that is easily magnetized and demagnetized, and used in telephones equipment.
• It possesses high magnetic permeability which is of the order of 30 times that of soft iron.
• This alloy responds even under weak magnetizing forces.
• Because of this property, this alloy is used extensively in communication engineering, especially in long-distance telephony.		 Comments Active
35 Which of the following options is used for mixing air with fuel supply? Blowdown valve Chimney Fusible plug Booster fan d Blowdown valve: Used to remove sludge/sediment or reduce pressure in boilers. Not related to air-fuel mixing.
Chimney: Used to exhaust flue gases. No role in mixing air and fuel.
Fusible plug: A safety device in boilers that melts at high temperature to release steam and prevent overheating.
Booster fan: A fan used in systems like mechanical draft furnaces or boilers. Helps in forcing air into the furnace where it mixes with fuel (solid, liquid, or gas).Enhances combustion efficiency by ensuring a better air-fuel mixture.		 Comments Active
36 What is the purpose of using the meter rod and economizer device in some carburetors? Idling Acceleration Cold starting Power enrichment d An economizer is a valve which remain closed at normal cruise operation and gets opened to supply rich mixture at full – throttle operation. It regulates the additional fuel supply during full – throttle operation. It should more appropriately be called power enrichment system. Comments Active
37 The equation to determine number of buckets (vanes) in terms of runner diameter (D) and jet diameter (d) of the Pelton tubine is: \(Z=(\frac{3D}{d})+15\) \(Z=(\frac{D}{2d})+15\) \(Z=(\frac{2D}{d})+15\) \(Z=(\frac{D}{2d})+30\) b \( Z=(\frac{D}{2d})+15\)
D = diameter of runner, d= diameter of jet, Z= no of bucket		 Comments Active
38 What is the minimum valley angle of an ash hopper used in a dry electrostatic precipitator? 55áµ’ 25áµ’ 45áµ’ 35áµ’ a Electrostatic Precipitator Hoppers:
Electrostatic precipitator hopper has the advantage of higher efficiency, low-pressure drop, easy removal of collected particles, and capacity of handling a large volume of flue gases.
The minimum valley angle of an ash hopper used in a dry electrostatic precipitator is generally 55 \(°\)		 Comments Active
39 Intercooling and reheating is used to increase the efficiency of the: Dual cycle Brayton cycle Otto cycle Ericsson cycle b Intercooling reduces the work of compression, reheating increases the work of expansion, and regeneration recovers heat from the exhaust gases. These processes result in higher efficiency. Comments Active
40 What is a locomotive boiler? Self- cooled boiler Horizontal water tube boiler Vertical water tube boiler Fire tube boiler d Locomotive boiler is a multi-tubular boiler and it has a horizontal drum axis. The circulation in the locomotive boiler is natural, also it is a medium pressure boiler, the draft is artificial, forced circulation, mobile, solid fuel fired fire tube boiler. Comments Active
41 Supercharging in diesel engines is done primarily to: Reduce exhaust losses Increase specific output Improve thermal efficiency Improve mechanical efficiency b Purpose of supercharging:
Provides better mixing of the air – fuel mixture
Increase the volumetric efficiency
Increase the power output of the engine
It tends to increase the possibility of detonation in an S.I. engine and lessen the possibility of knocking in a C.I. engine.		 Comments Active
42 For a fully-developed flow of water in a pipe having diameter 10 cm, velocity 0.2 m/s and kinematic viscosity 10-5 m2/s, what is the value of the Darcy friction factor? 6.4 0.032 0.64 0.064 b Darcy friction factor is define as,
\(f=\frac{64}{Re} where, Re=Raynolds no.\)
\(Re=\frac{ρVD}{μ}=\frac{VD}{ѵ}\)
Where, = density of fluid, V = velocity of fluid, D = Diameter of pipe, \(ρ\)
\(ѵ=kinematic viscosity\)
If Re > 4000 then the flow becomes turbulent flow
If Re < 2000 then the flow become laminar flow
Given D = 10 cm = 0.1m, v = 0.2 m/s, v = 10-5 m2/s
\(Re=\frac{0.1×0.2}{10^{-5}}=2000\)
Therefore, it is laminar flow
\(f=\frac{64}{2000}=0.032\)		 Comments Active
43 The deflection at the centre of a fixed – fixed beam carrying a point load at the centre is related to the deflection of simply supported beam by a factor of: 1 0.50 0.25 0.75 c Deflection at the center of a fixed - fixed beam carrying a point load at the center is yc= And deflection of the simply supported beam carrying a point load at the center is yc = Hence equating them we can say that Deflection at the center of a fixed - fixed beam carrying a point load at the center = 0.25 x deflection of the simply supported beam carrying a point load at the center. \(\frac{PL^{3}}{192EI}\) \(\frac{PL^{3}}{48EI}\) Comments Active
44 Chromium is stainless steel provides: Less ductility Low toughness Hardenability Corrosion resistance d Stainless steel: Steel (Carbon steel) is composed of Iron and carbon, which is the main component of stainless steel.
• Stainless steel differs from carbon steel by the amount chromium present, which is added to make it resistant to rust.
• Stainless steel, also known as inoxidable steel, nickel, and a minimum of 10.5% chromium.
• Stainless steel is notable for its corrosion resistance, and it is widely used for food handling and cutlery among many other applications.
An alloy is a substance made by melting two or more elements together, at least one of the metal.
Name of the alloy
Made up of
Brass
Copper and Zinc
Bronze
Copper and Tin
Stainless steel
Iron, chromium, Nickel, Carbon
German Silver
Copper, Zinc, and Nickel
Nickel Steel
Iron and Nickel		 Comments Active
45 Vacuum pressure is: \(\frac{Atmospheric pressure}{Absolute pressure}\) Atmospheric pressure – Absolute pressure Atmospheric pressure + Absolute pressure Atmospheric pressure × Absolute pressure b Fluid pressure s can be measured with reference to any arbitrary datum.
The common datum is
1. Absolute zero pressure
2. Local atmospheric pressure

When absolute zero (complete vacuum) is used as a datum, the pressure difference is called an absolute pressure, Pabs.
• When the pressure difference is measured either above or below local atmospheric pressure, Plocal, as a datum, it is called the gauge pressure.
• Local atmospheric pressure can be measured by a mercury barometer.
• The relationship between the above pressures is given as,
• Absolute pressure = Atmospheric pressure + Gauge pressure
\(P_{abs}=P_{atm}+P_{gauge}\)
• Vacuum pressure = Atmospheric pressure - Absolute pressure
\(P_{vaccum}=P_{atm}-P_{abs}\)		 Comments Active
46 The power developed by a turbine in a certain steam power plant is 1206 kW. The heat supplied to boiler is 3500 kJ/kg. The heat rejected by steam to cooking water is 2900 kJ/kg. The feed pump work required to condensate back into the boiler is 6 kW. What will be mass flow rate of cycle? 2 kg/s 0.002 kg/s 0.00622 kg/s 6.22 kg/s a Given
\(Q_{supp}=3500 kJ/Kg\)
\(Q_{rej}=2900 KJ/Kg\)
\(W_{tur}=1206 KW\)
\(Q_{pump}=6 KW\)
\(W_{net}=Q_{S}-Q_{R}\)
\(=3500-2900\)
\(W_{net}=600 KJ/Kg\)
…(1) \(W_{net}=600×m KJ\)
Here, \(W=W_{T}-W_{P}\)
..(2) \(W=1206-6W=1200 KJ/S \)
On comparing (1) and (2) eqn.
\(m=\frac{1200}{600}\)
\(m=2 Kg/S\)		 Comments Active
47 Bull’s eye refers to a type of: flow measurement gauge bi-colour gauge pressure gauge manometric gauge b Bi-colour gauges have wedge-shaped glasses to provide differential refraction to light in steam and water space. Otherwise, they are similar to the transparent gauges. An illuminator is located at the rear of the gauge with red and green colour slides fixed in place. It provides red colour for steam and green colour for water as the light gets deflected sideways.
Port-type bi-colour also known as Bull's eye gauges employ the bi-colour action with port-type glasses. This design is suitable up to -220 bar, the highest pressure for which steam drums are employed.		 Comments Active
48 What is a Babcock and Wilcox boiler? Horizontal fine tube boiler Water tube boiler Transverse fire tube boiler Vertical fire tube boiler b Babcock and Wilcox boiler is a water tube boiler, used in steam power plants. In this type of boiler, water is circulated inside the tubes and hot gases flow over the tubes. Comments Active
49 Number of links (l) and the number of joints (J) for a single degree of freedom kinematic chain, with only lower pair joints, is related by the expression: J = 2.5l – 1 J = 1.5l – 2 J = 2.5l – 2 J = 1.5l – 1 b For a simple mechanism, the degree of freedom (F) is given by the Grubler’s criterion:
F = 3(L-1) -2J –h
\(F=1,\)
\( 1=3l-3-2j\)
\(=3l-2j=4,\)
\( j=1.5l-2\)		 Comments Active
50 If the thermal efficiencies of mercury and steam cycles are respectively and, then the overall efficiency of a binary cycle can be expressed as: \(η_{1}\) \(η_{2}\) \(η_{1}-η_{2}\) \(η_{1}+η_{2}+η_{1}η_{2}\) \(η_{1}+η_{2}\) \(η_{1}+η_{2}-η_{1}η_{2}\) d formula for overall efficiency ηoverall of a binary cycle is: ηoverall=η1 + (1-η1) η2
Expanding this, we get overall efficiency = \(η_{1}+η_{2}-η_{1}η_{2}\)		 Comments Active
51 The type of flow for which the density is constant for a fluid flow is: Incompressible Compressible Uniform Non-uniform a Incompressible flow- a flow in which density of fluid remains same is known as incompressible fluid.
Compressible flow- a flow during which density of fluid changes is known as compressible fluid flow.		 Comments Active
52 The pressure intensity at a point in a fluid is given by 3.92 N/cm2. Find the corresponding height of the fluid, when the fluid is oil of specific gravity 0.9. 7.77 m 6.66 m 5.55 m 4.44 m d According to Hydrostatic Law:
Pressure intensity at a point:
\(P=3.92 N/cm^{2}=3.92×10^{4}N/m^{2}\)
\(P=ρgH\)
\(3.92×10^{4}=0.9×1000×9.81×H\)
\(h=\frac{3.92×10^{4}}{0.9×1000×10}=4.439m\)
\(∴h=4.44m\)		 Comments Active
53 Above critical pressure ratio, addition of regenerator in Brayton cycle causes one of the following: Lower compressor discharge temperature than turbine exhaust gas temperature No effect in cycle efficiency Gain in cycle efficiency Loss in cycle efficiency d The addition of regenerator after a certain (critical) pressure ratio regeneration becomes ineffective, decreases the cycle efficiency in Brayton cycle. Comments Active
54 The ability of oil to resist oxidation that would yield acids, lacquers and sludge is called: Foaming Oiliness Detergency Stability d • The ability of oil to resist oxidation that would yield acids, lacquers and sludge is called stability.
• Oil stability demands low temperature (under 90° C) operation and the removal of all hot areas from contact of the oil.
• Oxidation stability is a chemical reaction that occurs with a combination of the lubricating oil and oxygen.
• The rate of oxidation is accelerated by high temperatures, water, acids and catalysts such as copper. The rate of oxidation increases with time.
•The service life of a lubricant is also reduced with increases in temperature.
• Oxidation will lead to an increase in the oil's viscosity and deposits of varnish and sludge.		 Comments Active
55 In a refrigeration system, why are expansion devices located closer to the evaporator? To maximize the heat gain To ease the flow of the refrigerant To minimize the heat gain To avoid the flow of the refrigerant c The purpose of the expansion device is to rapidly reduce the pressure of the refrigerant in the refrigeration cycle. This allows the refrigerant to rapidly cool before entering the evaporator. Expansion device located closer to the evaporator in order to minimize the heat gain. Comments Active
56 An adiabatic heat exchanger is used to heat cold water at 15áµ’C entering at the rate of 10 kg/sec by hot air at 90áµ’C entering at the rate of 10 kg/sec. if the exit temperature of hot air is 20áµ’C, then find the exit temperature of cold water. for air = 1.008 kJ/kg, for water = 4.18 kJ/kg: \(C_{p} \) \(C_{p}=\) 89.12áµ’C 58.65áµ’C 31.88áµ’C 26.54áµ’C c Adiabatic heat exchanger: no heat loss to surroundings.
Heat lost by hot air = Heat gained by cold water.
( = ( \(m×c_{p}(T_{2}-T_{1})_{air}\) \(m×c_{p}(T_{2}-T_{1})_{water}\)
\(10×1.008(90-20)=10×4.18(T_{2}-15), T_{2}=31.88℃\)		 Comments Active
57 The efficiency of a Carnot engine is given by 0.80. If the cycle direction is reversed, then what will be the COP for the Carnot refrigerator? 0.33 0.25 0.30 0.27 b Given:
\( n_{carnot}=0.80,\)
\(Cop_{heat}_{pump}=\frac{1}{n_{carnot}}=\frac{1}{0.80}=1.25,\)
\(Cop_{refrigerator}=Cop_{hp}-1=1.25-1=0.25\)		 Comments Active
58 A heat engine is supplied with 450 kJ/s of heat at a constant fixed temperature of 227áµ’C. The heat is rejected at 27áµ’C. What will be the amount of heat rejected if the cycle is reversible? 300 kW 330 kW 320 kW 270 kW d Given:
\(Q_{1}=\frac{450KJ}{S}=450KW,\)
\(T_{1}=227+273=500K,\)
K \(T_{2}=27+273=300\)
\(n_{carnot}=\frac{work(W)}{heat supplied(Q_{1})}=\frac{T_{1}-T_{2}}{T_{1}}\)
= \( \frac{W}{450} \) \(\frac{500-300}{500}=120KW,\)
\(W=Q_{1}-Q_{2} ,\)
\(120=450-Q_{2},\)
\(Q_{2}=270KW\)		 Comments Active
59 The flow ratio for a Francis turbine varies from: 0.01 to 0.10 0.30 to 0.45 0.15 to 0.30 0.10 to 0.14 c Solution:  Flow Ratio = \(\frac{v_{f1}}{2gh}\)
Flow ratio for a Francis turbine 0.15 to 0.30		 Comments Active
60 What will be the magnitude of the shear stress on the principal plane? Zero Maximum Negative Minimum a
On principal plane shear stress will be zero.		 Comments Active
61 What is the number of buckets on the runner of a Pelton turbine if the jet ratio is 12? 6 13 21 20 c number of bucket= M/2 +15=12/2+15=21
Where m=jet ratio		 Comments Active
62 A centrifugal pump has the following specifications; 0.15 m diameter, 100 m long pipe with velocity of water 2.26 m/s, and friction factor 0.015. What is the frictional head loss? 13.8 15.1 10.4 12.6 c according to Darcy’s formula, \(h_{f}=\frac{4flv^{2}}{2gd}=\frac{4×0.015×100×2.26^{2}}{2×9.8×0.15}=10.41\) Comments Active
63 Diffusor increases the pressure of a fluid at the expense of it’s: Potential energy Impact energy Kinetic energy Rotational energy c Diffuser is a mechanical device that is used to increase the pressure at the expense of kinetic energy. Kinetic energy is higher at the inlet than that of the outlet. Comments Active
64 The enthalpies at the beginning of compression, at the end of compression and at end of condensation are 180 kJ/kg, 200 kJ/kg and 90 kJ/kg respectively. Determine COP of the vapour compression refrigeration system. 6 5 5.5 4.5 d Given
\(h_{3}=h_{4}=90KJ/kg \)
\(h_{1}=180 KJ/kg\)
\(h_{2}=200 KJ/kg\)

\(COP=\frac{Refrigerating effect}{Work done by compressor}\)
\(COP=\frac{R.E}{Wc}=\frac{h_{1}-h_{4}}{h_{2}-h_{1}}\)
\(∴\frac{180-90}{200-180}=4.5\)		 Comments Active
65 An oil of specific gravity 0.8 is flowing through a venture meter having inlet diameter 20 cm and throat diameter of 10 cm. The oil differential monometer shows a reading of 25 cm. Calculate the difference of pressure head. Specific gravity of mercury is 13.6. 400 cm 100 cm 300 cm 200 cm a Specific gravity of oil, So=0.8
Diameter at inlet D1=20 cm
Diameter at throat D2=10 cm
Manometer reading (differential height), h=25 cm=0.25 m
Specific gravity of mercury SHg=13.6
=400cm \(h_{p}=h(\frac{S_{hg}}{S_{o}}-1)=0.25(\frac{13.6}{0.8}-1)=4.0 m of oil\)		 Comments Active
66 Select the option that correctly matches the items given in List I to those given in List II.
List - I
List – II		 A – 3, B – 4, C – 2, D – 1 A – 3, B – 4, C – 1, D – 2 A – 4, B – 3, C – 2, D – 1 A – 4, B – 3, C – 1, D – 2 c Comments Active
67 What type of steel is generally used for connecting rods, crank shafts and axle components? Low carbon steel Mild steel Medium carbon steel High carbon steel c Medium carbon steel: For medium carbon steel, the carbon percentage varies from 0.3 to 0.8%.
• These steels have better strength and are not very easy to shape as mild steel.
• The hardness is slightly higher, and ductility is poor.
• The machine parts requiring strength like springs, automobile parts, connecting rods, axles, crankshafts, dies for forging, etc. are made from medium carbon steel.		 Comments Active
68 The platform of the boiler where burning of fuel takes place is known as: Lagging Shell Setting Grate d The grate is a platform in the combustion chamber where fuel is burnt. The grate is generally a cast-iron bar and there is space between them so the air can pass through it. The surface area of the grate where fire takes place called a grate surface. Comments Active
69 Which of the following is true for performance parameters of vapour power cycles? Work ratio = 1 + Back work ratio Work ratio = Back work ratio Work ratio = 1 – Back work ratio Work ratio = 2 + Back work ratio c Work ratio = 1 – Back work ratio
\(Work ratio=\frac{Net work output}{Turbine work output} \)
\( Back work ratio=\frac{Pump work input}{Turbine work output}\)		 Comments Active
70 Which of the following statements is true? Rankine efficiency is equal to Carnot efficiency. Rankine efficiency is lower than Carnot efficiency. Rankine efficiency is higher than Carnot efficiency. Rankine efficiency cannot be compared with Carnot efficiency. b Rankine efficiency is lower than Carnot efficiency. The Rankine cycle, which is used in steam power plants, involves phase changes (boiler and condenser) and irreversible processes (like pumping and expansion in turbine), making it less efficient than the Carnot cycle operating between the same temperature limits. Comments Active
71 Which of the following boiler mountings protect the boiler against damage due to overheating due to low water level? Blow off cock Stop valve Feed check valve Fusible plug d The fusible plug consists of tin or lead alloy of low melting point. The fusible plug puts off the fire in the furnace of the steam boiler as the water level falls below the safe level and thus prevents the explosion that may result from overheating of the tubes and the shell. Comments Active
72 Gibbs phase rule defines the relationship between degree of freedom (F) of a system, member of phases (P) and the number of components (C). What is the equation? F – P = C F + P = C + 1 F + P = C + 2 F + P = C c P + F = C + 2 P = No. of phases, F = Degrees of freedom, C = No. of components Comments Active
73 Tool steel contains carbon in the range of: 0.5 to 1.5 0.1 to 0.3 0.3 to 0.6 0.2 to 0.9 a Tool steel is a type of high carbon steel, usually containing 0.7% to 1.5% carbon, and alloying elements like tungsten, molybdenum, chromium, vanadium, etc. for improved wear resistance, hardness, and toughness.
High Carbon steel: The carbon percentage varies from 0.7 to 1.5%.
• A high percentage of carbon gives hardness and strength to the metal.
• It is mainly used for tools like chisels, hammers, dies, punches, broaches, reamers, drills, taps, etc. and the machine parts like springs, mandrels and similar parts requiring high strength and hardness.		 Comments Active
74 What is the absolute pressure at a point 3 m below the free surface of a liquid having a density of 1.53 ×103 kg/m3 if the atmospheric pressure is equivalent to 750 mm of mercury? The specific gravity of mercury is 13.6 and density of water is 1000 kg/m3. 345090 N/m2 245090 N/m2 145090 N/m2 45090 N/m2 c \(h=3 m, ρ_{liquid}=1.53×10^{3}kg/m^{3}\)
\(h_{atm}=750 mm of mercury (Hg)=0.75m,\)
\(specific gravity, S_{Hg}=13.6, ρ=13.6×1000 kg/m^{3}\)
\(P_{atm}=ρgh_{atm}=13.6×1000×9.81×0.75=100,062 N/m^{2}\)
\(P_{abs}=P_{atm}+P_{gauge}\)
\(P_{gauge}=(ρgh)_{liquid}=1.53×10^{3}×9.81×3=45027.9N/m^{2}\)
\(P_{abs}=P_{atm}+P_{gauge}=100062+45027.9=145090 N/m^{2}\)		 Comments Active
75 What will be the effect if by mistake diesel fuel is supplied in a petrol engine? Engine will give dense smoke and will consume more fuel as well as lubricating oil Engine will run at lower rpm Engine will run at reduced efficiency Engine will not run d Petrol engines rely on spark ignition, where the air-fuel mixture is ignited by a spark from the spark plug.
Diesel fuel has a higher flashpoint (around 52–96°C) compared to petrol (around -43°C), meaning it is less volatile and does not vaporize easily at ambient temperatures.
Since petrol engines require vaporized fuel for proper combustion in the cylinder, diesel fuel will not vaporize properly in the carburetor or fuel injection system designed for petrol.
Diesel’s higher viscosity and poor volatility will clog the carburetor or fuel injectors, and the spark plugs may foul.
Consequently, the petrol engine will fail to ignite the fuel-air mixture, and the engine will not run.		 Comments Active
76 An engine at full load delivers 200 kW brake power. It requires 25 kW to rotate it without fuel at the same speed. The mechanical efficiency at half load is: 50% 80% 66.7% 25% b Mechanical efficiency at half load \(=\frac{BP}{BP+FP}\)
Given: Brake power (BP) = 200 kW, Half load = 100 kW Friction Power (FP) = 25 kW
Mechanical efficiency at half load = \(\frac{BP}{BP+FP}\)
Mechanical efficiency at half load = \(\frac{100}{125}\)
Mechanical efficiency at half load = 0.8 ⇒ 80%		 Comments Active
77 The thermal efficiency of an air standard Brayton cycle in terms of pressure ratio (rp) and γ (Cp/Cv) is: \(1-\frac{1}{(r_{p})^{γ}}\) \(1-\frac{1}{(r_{p})^{γ-1/γ}}\) \(1-\frac{1}{(r_{p})^{γ-1}}\) \(1-\frac{1}{(r_{p})^{\frac{1}{γ}}}\) b The thermal efficiency of an air standard Brayton cycle is given by:
\(η_{t}=1-\frac{1}{rp\frac{γ-1}{γ}}\)
Where, rp = pressure ratio = and = ratio of specific heats. \(\frac{p_{2}}{p_{1}}=\frac{p_{3}}{p_{4}}\) \(γ\)		 Comments Active
78 What is the typical composition of the castings employed in oil – fired boilers? 50% Ni and 50% Cr 80% Ni and 20% Cr 70% Ni and 30% Cr 90% Ni and 10% Cr a In oil-fired boilers that use oil with high V and S, the parts are to be made with even higher Cr and Ni to resist ash corrosion in addition to temperature.
The casting employed typically contain
50% Cr- 50% Ni
60% Cr-40% Ni		 Comments Active
79 Select the option that correctly matches the items given in List I (details of the process of the cycle) to those given in List – II (name of the cycle).
List - I
List – II		 A – 3, B – 4, C – 2, D – 1 A – 4, B – 3, C – 1, D – 2 A – 4, B – 3, C – 2, D – 1 A – 3, B – 4, C – 1, D – 2 d (1) Otto cycle: Two isentropic and tow constant volume processes.

(2) Ericsson cycle: Two isothermals and two isobaric processes.

(3) Stirling cycle: Two isothermals and two constant volume processes.

(4) Brayton cycle/Joule cycle: Two isentropic and two isobaric processes.
 Comments Active
80 For a floating body to be in a stable equilibrium, where G is the centre of gravity, B is the centre of buoyancy, and M is the metacenter, which of the following statement is true? M and B coincide M is above G M is below G M and G coincide b
• 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
81 Which of the following is an example of a thixotropic substance? Printer ink Water Quick sand Gypsum a Thixotropic: Apparent viscosity for thixotropic fluids decreases with time under constant applied shear stress.
Example: Crude oil, lipstick, certain paints, and Printing Ink.		 Comments Active
82 Stream line in a flow is; locus of fluid particles that have earlier passed through a given point tangent to the acceleration vector at any instant in time tangent to the velocity vector at any instant in time actual path followed by a fluid particle c Streamlines: Streamlines are a family of curves that are instantaneously tangent to the velocity vector of the flow.
• These show the direction in which a massless fluid element will travel at any point in time.
Streaklines: Streaklines are the locus of points of all the fluid particles that have passed continuously through a particular spatial point in the past.
• Dye steadily injected into the fluid at a fixed point extends along a streak line.
Pathlines: pathlines are the trajectories that individual fluid particles follow.
• These can be thought of as "recording" the path of a fluid element in the flow over a certain period.
• The direction the path takes will be determined by the streamlines of the fluid at each moment in time.		 Comments Active
83 A stone of mass ‘m’ at the end of a string of length ‘l’ is whirled in a vertical circle at a constant speed. What position of the stone shall result in the maximum tension in the string? Half – way down from the top At the top – way of the circle At the bottom of the circle Quarter – way down from the top c Tension is maximum at the bottom, because both centripetal force and gravitational force act in the same direction (towards the center).
ï‚· At the top, gravitational force helps provide centripetal force, reducing the tension.		 Comments Active
84 An oil of specific gravity 0.9 is contained in a vessel. At a point the height of oil is 40 m. find the corresponding height of water at that point. 42 m 52 m 36 m 46 m c Hydrostatic pressure of fluid is given by,
\(P=ρgh\)
Where, \(ρ=Density of fluid, g=Acceleration due to gravity and h=height of water surface\)
Specific gravity of oil = 0.9
Density of oil, \(ρ=0.9×density of water=0.9×1000=900 kg/m^{3}\)
This is solved by using Pascal’s Law, which states that pressure at all the points in a horizontal direction will be same.
Pressure due to oil height = pressure due water height
\((ρgh)_{oil}=(ρgh)_{water}\)
\(900×9.81×40=1000×9.81×h\)
\(∴h=36m of water column\)		 Comments Active
85 Which of the following is NOT a wet sump lubrication system? Pressure feed system Velocity feed system Splash system Splash and pressure system b Wet sump lubrication system: In a wet sump system, the oil is stored in the crankcase (sump) and circulated within the engine using various mechanisms.
Common types of wet sump systems include:
Pressure feed system
Splash system
Splash and pressure system		 Comments Active
86 The atmospheric air at DBT is 20ᵒC. It enters a heating coil which is maintained 50ᵒC. If the air leaves the heating coil at 35ᵒC, then what will be the efficiency of the coil? 0.6 0.5 0.35 0.22 b η \( =\frac{T_{out}-T_{in}}{T_{coil}-T_{in}}\)
= \(\frac{35-20}{50-20}\)
= \(\frac{15}{30}=0.5=50%\)		 Comments Active
87 The by-pass factor of a single cooling coil in an air-conditioner is 0.8. What will be the by-pass factor it three such cooling coils, with the same apparatus dew point, are kept one behind the other? 0.102 0.226 0.343 0.512 d When multiple coils are placed one behind the other, the combined by-pass factor is the product of the individual by-pass factors: \(BPF_{total}=(BPF)^{n}\)
Where:
BPF = by-pass factor of one coil = 0.8
n= number of coils = 3
= \(0.8^{3}=0.512 \)		 Comments Active
88 The ratio of clearance volume to the displacement volume of an R12 reciprocating compressor is 0.06 specific volume at inlet and outlet compressor are 0.03 and 0.01 m3/kg, respectively. Volumetric efficiency of the compressor is: 82% 76.4% 95% 88% d Given
C = 0.06
V1 = 0.03 m3/Kg
V2 = 0.01 m3/Kg
\(η_{v}=1-C-C(\frac{P_{2}}{P_{1}})^{1/γ}\)
\(=1+C-C(\frac{V_{1}}{V_{2}})\)
\(=1+0.06-0.06×\frac{0.03}{0.01}\)
\(η_{v}=0.88\)		 Comments Active
89 The function of piston rings in internal combustion engines is also to: Increase the speed Cool the cylinder Dissipate heat to cylinder walls Prevent piston from corrosion c Piston rings fulfill the following important tasks for engine operation:
Sealing of the combustion chamber, in order to maintain the pressure of the combustion gas. The combustion gas must not enter the crankcase, and oil must not reach the combution chamber.
Transfer of heat built up in the piston to the cylinder surface.
Controlliing the oil balance, where a minium of oil is needed on the cylinder surface to creaste a hydrodnamic situation, while oil consumption needs to be kept as low as possible.
These tasks are performed by the piston rings as follows:
1st piston ring:
Compression of combustion air or gas mixture, and the resulting gas pressure in the combution cycle, transfer of generated heat to the cylinder surface, and to a slight degree, scraping of the residual oil from the cylinder surface.
2nd piston ring:
Support of the remaining gas pressure due to blow – by past the 1st piston ring scraping of oil from, and transfer of generated heat to the cylinder surface.
3rd piston ring:
Scraping of the oil.		 Comments Active
90 Dynamic viscosity increases with the rate of shear increase for: rheopectic fluid pseudoplastic fluid thixotropic fluid dilatant fluid d Thixotropic Fluid: Fluids for which dynamic viscosity decreases with the time are termed as thixotropic fluids. Example- Lipstick, Crude Oil, etc.
Pseudoplastic Fluid: Non-Newtonian fluid for which dynamic viscosity decreases with an increase in the shear stress is termed as pseudoplastic fluid. Example- Blood, Paints, etc.
Dilatant Fluid: Non-Newtonian fluid for which dynamic viscosity increases with an increase in the shear stress is termed as dilatant fluid. Example- Sugar suspension, Starch suspension, etc.
Rheopectic Fluid: Fluids for which dynamic viscosity increases with the time are termed as rheopectic fluids. Example- Gypsum, Bentonite solutions etc.		 Comments Active
91 In a diesel engine, where does the mixing of fuel and air occur? Inlet manifold Fuel pump Injector Engine cylinder d In diesel engines, only air is sent into the combustion chamber during suction. This air is compressed during the compression stroke and towards the end of the compression stroke, fuel is injected by the fuel injection system into the cylinder – just before the desired start of combustion. Liquid fuel is injected at high velocities as one or more jets through small orifices or nozzles in the injector tip.
Since the air temperature and pressure are above the fuel’s ignition point, spontaneous ignition of portions of already mixed fuel and air occurs after a delay period of a few crank angle degrees.
So, in the case of a diesel engine, the mixing of fuel and air takes place in the engine cylinder.		 Comments Active
92 Select the option that correctly matches the items given in List I to those given in List II.
List - I
List – II		 A – 3, B – 4, C – 2, D – 1 A – 4, B – 3, C – 2, D – 1 A – 4, B – 3, C – 1, D – 2 A – 3, B – 4, C – 1, D – 2 c Rotational flow:
• Fluid particle is rotating about their mass own center.
• For rotation, some torque is required and this is created by shear force due to viscosity.
• A non-viscous fluid can never be rotational.
• Vorticity exists due to the rotational component.
• Stream function (ψ) does not satisfy the Laplace equation for rotational flow.
Irrotational flow:
• A fluid particle does not rotate about its mass own center.
• Vorticity is zero because there is no rotational component.
• Stream function (ψ) satisfy the Laplace equation for irrotational flow.
• Velocity potential function ($) exist only for irrotational flow.
Singularities:
• When different types of fluid flow merge at a single point then singularities are formed and at this point, velocity is zero or infinite.
Streamline:
• Streamlines are the lines drawn through the flow field in such a manner that the velocity vector of the fluid at every point on the streamline is tangent to the streamline at that instant.
• Using the continuity equation it can be shown that the speed of flow is inversely proportional to the spacing between streamlines.
• The streamline also gets divided at upstream of the body and again joins on downstream.
• Streamline that follows the flow division is called a dividing streamline.
• The point at which the division takes place is called a stagnation point, and the velocity of the fluid at the stagnation point is zero.		 Comments Active
93 What is the range of length of a Cornish boiler? 15 to 50 m 10 to 15 m 4 to 8 m 1 to 2 m 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
94 A hydraulic press has a ram of 20 cm diameter and a plunger of 3 cm diameter. It is used for lifting a weight of 30 kN. Find the force registered at the plunger 1075 N 975 N 675 N d Diameter of plunger, d = 3 cm, Diameter of ram, D = 20 cm, Force required at the plunger =?, Weight = 30 kN
According to Pascals law,
Pressure applied at ram = Pressure exerted on the plunger
\(\frac{F_{1}}{A_{1}}=\frac{F_{2}}{A_{2}}\)
\(\frac{30000}{\frac{Ï€D^{2}}{4}}=\frac{F_{2}}{\frac{Ï€d^{2}}{4}}\)
\(∴F_{2}=\frac{d^{2}}{D^{2}}×30000=\frac{3^{2}}{20^{2}}×30000=675 N\)
Here, F2 = force required on the plunger		 Comments Active
95 What does a Lagrangian description of fluid flow provide? Energy of a fluid particle at every time instant Position of a fluid particle at every time instant Pressure at a given point at every time instant Temperature at a given point at every time instant b Lagrangion Description: The Lagrangian Description is one in which Individual fluid particles are tracked, much like the tracking of billiard balls in a high school physics experiment.
• In the Lagrangian description of fluid flow, individual fluid particles are "marked," and their positions, velocities, etc. are described as a function of time.
• The physical laws, such as Newton's laws and conservation of mass and energy, apply directly to each particle.
• However, fluid flow is a continuum phenomenon, at least down to the molecular level. It is not possible to track each "particle" in a complex flow field.
• Thus, the Lagrangian description is rarely used in fluid mechanics.
Eulerian Description: The Eulerian Description is one in which a control volume is defined, within which fluid flow properties of interest are expressed as field
• In the Eulerian description of fluid flow, individual fluid particles are not identified. Instead, a control volume is defined.
• In the Eulerian description of fluid flow, one is not concerned about the location or velocity of any particular particle, but rather about the velocity, acceleration, etc. of whatever particle happens to be at a particular location of interest at a particular time.
• Since fluid flow is a continuum phenomenon, at least down to the molecular level, the Eulerian description is usually preferred in fluid mechanics.		 Comments Active
96 The range of coefficient of discharge value of a Venturimeter is: 0.6 to 0.8 0.25 to 0.35 0.55 to 0.75 0.95 to 0.99 d The coefficient of discharge is the ratio of actual discharge to theoretical discharge.
Venturimeter – 0.95 to 0.99
Orifice meter – 0.62 to 0.65
Nozzle meter – 0.93 to 0.98		 Comments Active
97 The mechanism which serves the purpose of dividing the periphery of a circular piece into a number of equal parts is known as: Oldham Indexing Quick return Slider crank b Indexing is an operation of dividing a periphery of a cylindrical workpiece into equal number of divisions by the help of index crank and index plate. Comments Active
98 A Newtonian fluid fills the clearance between a shaft and a sleeve. When a force of 0.9 kN is applied to the shaft parallel to the sleeve, the shaft attain a speed of 1.25 cm/s. What will be the speed of the shaft if a force of 3 kN is applied? 5.26 cm/s 6.32 cm/s 4.16 cm/s 5.19 cm/s c From Newton’s law of viscosity
\(τ=μ\frac{du}{dy}\)
We know that
\(F=τ×A\)
\(∴F=μ\frac{du}{dy}\)
\(∴\frac{F_{2}}{F_{1}}=\frac{u_{2}}{u_{1}}\)
Given \(F_{2}=3kN, F_{1}=0.9 kN, u_{1}=1.25 cm/s\)
\(∴\frac{F_{2}}{F_{1}}=\frac{u_{2}}{u_{1}}\)
\(∴\frac{3}{0.9}=\frac{u_{2}}{1.25}\)
\(∴u_{2}=4.166 cm/s\)		 Comments Active
99 Which of the following statements is/are correct with respect to a gas turbine power plant?
Statements:
P: Smaller in size compared to a steam power plant for the same power output
Q: Starts slowly compared to a steam power plant
R: Works on the principle of the Rankine cycle
S: Good compatibility with solid fuel		 All statements P, Q, R and S are correct Only statement P is correct Only statement S is correct Only statements P and Q are correct. b Gas turbines are compact and have a high power-to-weight ratio, making them smaller than steam power plants of equivalent capacity.
Gas turbines start quickly, often within minutes, unlike steam plants which require longer startup times due to boiler warm-up and pressure build-up.
Gas turbines operate on the Brayton cycle, not the Rankine cycle. The Rankine cycle is the principle behind steam power plants.
Gas turbines primarily use gaseous or liquid fuels. They are not well-suited for solid fuels, which are more typical in steam boilers.		 Comments Active
100 The specific volume of wet steam at 1600áµ’C, 80% quality, Vf = 0.011m3/kg and Vg = 0.3071 m3/kg is: 1.25 1.09 0.25 1 c X =80% = 0.80, Vf = 0.011m3/kg Vg = 0.3071 m3/kg
\(v=v_{f}+x(v_{g}-v_{f})\)
\(=0.011+0.8(0.3071-0.011)\)
\(=0.248=0.25m^{3} /kg\)		 Comments Active