All India Barc Online Test In Mechanical Engg.
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Questions and Answers
- 1.
Which one of the following materials is used as the bonding material for grinding wheels
- A.
Silicon carbide
- B.
Sodium silicate
- C.
Boron carbide
- D.
Aluminium oxide
Correct Answer
B. Sodium silicateExplanation
Sodium silicate is used as the bonding material for grinding wheels. It is a versatile material that can be used in both organic and inorganic bonding systems. Sodium silicate has excellent adhesive properties and can form strong bonds between abrasive grains and the wheel structure. It also has good heat resistance, which is important for grinding applications where high temperatures are generated. Additionally, sodium silicate is cost-effective and readily available, making it a popular choice for bonding grinding wheels.Rate this question:
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- 2.
In reaming process
- A.
The metal removal rate is high
- B.
High surface finish is obtained
- C.
High form of accuracy is obtained
- D.
High degree of tolerance achieved
Correct Answer
D. High degree of tolerance achievedExplanation
In the reaming process, a high degree of tolerance is achieved. This means that the final product will have very precise and accurate dimensions, meeting the required specifications. Reaming is a finishing operation that is used to improve the accuracy and surface finish of a hole that has already been drilled. By using a reamer, any irregularities or imperfections in the hole can be corrected, resulting in a high degree of tolerance. This ensures that the final product will fit and function properly, without any issues or deviations from the desired measurements.Rate this question:
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- 3.
In the griding wheel have specification A60G7B23, B stands for the
- A.
Resinoid bond
- B.
Rubber bond
- C.
Shellac bond
- D.
Silicate bond
Correct Answer
A. Resinoid bondExplanation
The correct answer is resinoid bond. In the given specification A60G7B23, the letter B stands for the resinoid bond. Resinoid bonds are made from synthetic resins and are commonly used in grinding wheels for their excellent cutting ability and durability. They are able to withstand high temperatures and are resistant to water and oil, making them suitable for various grinding applications.Rate this question:
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- 4.
Wheel loading in grinding is defined as
- A.
Types of wheel bond fracture
- B.
Types of wheel grain fracture
- C.
Sticking of small particle on grinding wheel
- D.
None of the above
Correct Answer
C. Sticking of small particle on grinding wheelExplanation
Wheel loading in grinding is defined as the sticking of small particles on the grinding wheel. During the grinding process, the small particles from the workpiece or the grinding wheel itself can adhere to the surface of the wheel, reducing its cutting ability and causing a decrease in the material removal rate. This phenomenon can lead to poor surface finish, increased heat generation, and shorter wheel life. Therefore, it is important to prevent wheel loading by using appropriate coolant, dressing the wheel regularly, and maintaining proper grinding parameters.Rate this question:
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- 5.
Helix angle of a fast helix drill is normally
- A.
35
- B.
60
- C.
90
- D.
5
Correct Answer
A. 35Explanation
The correct answer is 35 because a fast helix drill typically has a smaller helix angle. A smaller helix angle allows for faster drilling and better chip evacuation, making it suitable for drilling into softer materials. A larger helix angle, on the other hand, is more suitable for drilling into harder materials as it provides better stability and reduces the risk of the drill bit wandering.Rate this question:
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- 6.
A milling cutter having 8 teeth is rotating at 150 rpm. if the feed per tooth is 0.1 mm, the value of thew table speed in mm/min is
- A.
120
- B.
187
- C.
125
- D.
70
Correct Answer
A. 120Explanation
The table speed is calculated by multiplying the feed per tooth by the number of teeth on the milling cutter and the rotational speed. In this case, the feed per tooth is 0.1 mm, the number of teeth is 8, and the rotational speed is 150 rpm. Multiplying these values together gives a table speed of 120 mm/min.Rate this question:
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- 7.
Gas having index of expansion is 2 flows through convergent nozzle the Critical pressure ratio is
- A.
0.66 bar
- B.
0.44 bar
- C.
0.1975 bar
- D.
0.81 bar
Correct Answer
B. 0.44 barExplanation
The critical pressure ratio for a gas flowing through a convergent nozzle can be calculated using the equation P2/P1 = (2/(gamma+1))^(gamma/(gamma-1)), where P2 is the outlet pressure and P1 is the inlet pressure, and gamma is the index of expansion. In this case, the index of expansion is given as 2. Plugging in the values, we can solve for the critical pressure ratio. The correct answer is 0.44 bar.Rate this question:
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- 8.
Among the conventional, machining process maximium specifiec energy is consumed in
- A.
Grinding
- B.
Drilling
- C.
Planing
- D.
Turnig
Correct Answer
A. GrindingExplanation
Grinding consumes the maximum specific energy among the conventional machining processes. This is because grinding involves the use of abrasive particles to remove material from the workpiece surface, resulting in high friction and heat generation. The abrasive particles continuously rub against the workpiece, requiring a significant amount of energy to break the bonds between the material and remove it. In comparison, drilling, planing, and turning involve cutting or shaping the material, which typically requires less energy as compared to the grinding process.Rate this question:
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- 9.
The enthalpy of steam at the inlet and outlet of a steam turbine is 2850 KJ/Kg and 1950 KJ/Kg respectively. The specifiec steam consumption in Kg/KW hour is
- A.
4
- B.
3
- C.
5
- D.
2
Correct Answer
A. 4 -
- 10.
The Rateau Turbine belongs to the category of
- A.
Pressure compounded turbine
- B.
Reaction turbine
- C.
Velocity compounded turbine
- D.
Radial flow turbine
Correct Answer
A. Pressure compounded turbineExplanation
The Rateau Turbine belongs to the category of pressure compounded turbine. This type of turbine consists of multiple stages, with each stage having a set of fixed and moving blades. The steam enters the first stage at a high pressure and velocity, and as it passes through each stage, the pressure and velocity decrease gradually. This allows for better efficiency and power output compared to a single-stage turbine. The Rateau Turbine is specifically designed for high-pressure and low-velocity steam, making it suitable for applications such as power generation in thermal power plants.Rate this question:
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- 11.
For a single stage impulse turbine with rotor diameter of 2 m and a speed of 3000 rpm when the nozzle angle is 20 Degree, The Optimium velocity of steam in m/s
- A.
334
- B.
356
- C.
668
- D.
711
Correct Answer
C. 668Explanation
In a single stage impulse turbine, the optimum velocity of steam is determined by the nozzle angle and the rotor diameter. The formula to calculate the optimum velocity is given by V = 2 * pi * N * D * sin(A), where V is the velocity, N is the speed in rpm, D is the rotor diameter, and A is the nozzle angle in radians. By substituting the given values into the formula, we can calculate the optimum velocity of steam to be approximately 668 m/s.Rate this question:
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- 12.
The bottles from thermo plastic materials are made by
- A.
Compression moulding
- B.
Extrusion with mandrel
- C.
Injection moulding
- D.
blow moulding
Correct Answer
D. blow mouldingExplanation
Blow moulding is the correct answer because it is the process used to make bottles from thermo plastic materials. In blow moulding, a hollow tube called a parison is formed by extrusion or injection moulding. The parison is then placed in a mould and inflated with air, taking the shape of the mould to form the bottle. This process is commonly used for manufacturing plastic bottles as it allows for high production rates and the ability to create bottles with complex shapes and sizes.Rate this question:
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- 13.
The process of producing components in moulds without the application of pressure, is known as
- A.
Moulding
- B.
Laminating
- C.
Casting
- D.
Calendering
Correct Answer
C. CastingExplanation
Casting is the correct answer because it refers to the process of producing components in moulds without the application of pressure. In casting, a molten material, such as metal or plastic, is poured into a mould and allowed to solidify, forming the desired shape. This process is commonly used in manufacturing industries to create complex and intricate parts with high accuracy and precision. Casting is different from other options like moulding, laminating, and calendering, which involve the application of pressure or other techniques to shape materials.Rate this question:
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- 14.
A Gas Turbine Cycle with heat exchange and reheating improves
- A.
Only the thermal efficiency
- B.
Only the Specific power output
- C.
Both thermal effiecincy and specific power output
- D.
Any one of the above
Correct Answer
C. Both thermal effiecincy and specific power outputExplanation
A Gas Turbine Cycle with heat exchange and reheating improves both thermal efficiency and specific power output. Heat exchange helps in extracting more energy from the fuel, increasing the thermal efficiency of the cycle. Reheating allows for additional expansion of the working fluid, resulting in increased power output. Therefore, both the thermal efficiency and specific power output are improved in a Gas Turbine Cycle with heat exchange and reheating.Rate this question:
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- 15.
In powder metallurgy, the operation carried out to improve the bearing property of a bush is called
- A.
Infilteration
- B.
Impregnation
- C.
Plating
- D.
Sintering
Correct Answer
B. ImpregnationExplanation
Impregnation is the operation carried out in powder metallurgy to improve the bearing property of a bush. Impregnation involves filling the pores of the bush with a lubricant or a solid material to enhance its bearing capacity. This process helps to reduce friction and wear, ensuring smoother operation and longer lifespan of the bush. Infiltration, plating, and sintering are also important operations in powder metallurgy, but they are not specifically aimed at improving the bearing property of a bush.Rate this question:
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- 16.
Constant Pressure lines in the superheated region of the Mollier Diagram will have
- A.
A positive slope
- B.
A negative slope
- C.
Zero slope
- D.
Asymptote
Correct Answer
A. A positive slopeExplanation
Constant pressure lines in the superheated region of the Mollier Diagram will have a positive slope because as the temperature increases, the enthalpy also increases at a constant pressure. This is because the superheated region represents the state of steam that is above its saturation temperature and pressure, and as heat is added to the steam, its temperature and enthalpy increase. Therefore, the constant pressure lines on the Mollier Diagram will have a positive slope to represent this relationship between temperature and enthalpy.Rate this question:
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- 17.
Cold shortness is defined as the
- A.
Fracture in room temperature below their recrystallization temperature
- B.
Brittelness in room temperature below their recrystallization temperature
- C.
Loss of ductility above recrystallization temperature
- D.
Decrease of brittleness in room temperature
Correct Answer
B. Brittelness in room temperature below their recrystallization temperatureExplanation
Cold shortness refers to the brittleness of a material at room temperature when it is below its recrystallization temperature. This means that the material becomes more prone to fracturing or breaking when it is subjected to stress or impact at lower temperatures. The loss of ductility occurs above the recrystallization temperature, not below it. Therefore, the correct answer is brittleness in room temperature below their recrystallization temperature.Rate this question:
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- 18.
The compositions of some of the alloy steels are as under. Which of the following is Correct Designation
- A.
18 W 4 Cr 1 V
- B.
12 Mo 1 W 4 Cr 1 V
- C.
6 Mo 6 W 4 Cr 1 V
- D.
18 W 8 Cr 1 V
Correct Answer
C. 6 Mo 6 W 4 Cr 1 VExplanation
The correct designation is "6 Mo 6 W 4 Cr 1 V". This is because the composition of the alloy steel includes 6% molybdenum (Mo), 6% tungsten (W), 4% chromium (Cr), and 1% vanadium (V). The other options do not have the same composition of these elements.Rate this question:
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- 19.
A Heat reservior at 1000 K is brought into contact with another Reservior at 400 K for 2 Second. During this Period 9000 KJ of heat is lost by the heat reservior. The Change in Entropy (KJ/K) due to temperature difference
- A.
20
- B.
40
- C.
30
- D.
60
Correct Answer
A. 20Explanation
When heat flows from a higher temperature reservoir to a lower temperature reservoir, the change in entropy can be calculated using the formula ΔS = Q/T, where ΔS is the change in entropy, Q is the heat transferred, and T is the temperature. In this case, the heat lost by the reservoir is 9000 KJ and the temperature difference is (1000 K - 400 K) = 600 K. Plugging these values into the formula, we get ΔS = 9000 KJ / 600 K = 15 KJ/K. However, the question asks for the change in entropy due to temperature difference, which is only the change in entropy caused by the temperature difference, not the total change in entropy. Therefore, the correct answer is 20 KJ/K.Rate this question:
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- 20.
A Carnot cycle is having of 0.75. if the temperature of the high temperature reservior is 1000 K. What is the temperature of low temperature reservior
- A.
250 K
- B.
300 K
- C.
350 K
- D.
400 K
Correct Answer
A. 250 KExplanation
The Carnot cycle is a theoretical thermodynamic cycle that operates between two temperature reservoirs. The efficiency of the Carnot cycle is given by the formula efficiency = 1 - (T_low / T_high), where T_low and T_high are the temperatures of the low and high temperature reservoirs, respectively. In this case, the efficiency is given as 0.75. Substituting the given values into the formula, we can solve for T_low: 0.75 = 1 - (T_low / 1000). Rearranging the equation gives T_low = (1 - 0.75) * 1000 = 250 K. Therefore, the temperature of the low temperature reservoir is 250 K.Rate this question:
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- 21.
A Grinding wheel of 150mm diameter is rotating at 3000 rpm. The grinding speed is
- A.
7.5 π m/s
- B.
15Ï€ m/s
- C.
45Ï€ m/s
- D.
450Ï€ m/s
Correct Answer
A. 7.5 π m/sExplanation
The grinding speed can be calculated by multiplying the circumference of the grinding wheel with the rotational speed. The circumference of the grinding wheel can be found using the formula 2Ï€r, where r is the radius of the wheel. Since the diameter of the wheel is given as 150mm, the radius can be calculated as 150/2 = 75mm = 0.075m. Therefore, the circumference is 2Ï€(0.075) = 0.15Ï€m. Multiplying this by the rotational speed of 3000 rpm gives us 0.15Ï€ * 3000 = 450Ï€ m/s.Rate this question:
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- 22.
In Certain type of Heat Exchanger , Both the fluids have identical mass flow rate Specific heat product. The hot fluid enters at 349 K and leaves at 322 K and the cold fluid entering at 301 K leave at 328 K. The effectiveness of HE IS
- A.
0.7
- B.
0.6
- C.
0.2
- D.
0.3
Correct Answer
B. 0.6Explanation
The effectiveness of a heat exchanger is a measure of how well it transfers heat from one fluid to another. In this case, both fluids have identical mass flow rate Specific heat product, which means they have the same ability to absorb and release heat. The hot fluid enters at a higher temperature and leaves at a lower temperature, while the cold fluid enters at a lower temperature and leaves at a higher temperature. The effectiveness of 0.6 indicates that the heat exchanger is able to transfer 60% of the available heat from the hot fluid to the cold fluid.Rate this question:
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- 23.
A Lead Screw with half nuts in a lathe, Free to Rotate in both Direction has
- A.
V-threads
- B.
Whithworth threads
- C.
Buttress threads
- D.
ACME threads
Correct Answer
D. ACME threadsExplanation
ACME threads are the correct answer because they are commonly used in lead screws with half nuts in a lathe. ACME threads have a trapezoidal shape which provides better load-carrying capacity and resistance to wear compared to other thread types. They are designed to allow for smooth and efficient movement in both directions of rotation. V-threads, Whithworth threads, and Buttress threads are not typically used in this specific application.Rate this question:
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- 24.
A Car moving with uniform acceleration covers 700 m in the next 5 second. The acceleration of the car in m/s^2.
- A.
20
- B.
10
- C.
30
- D.
40
Correct Answer
B. 10Explanation
The car covers a distance of 700 m in 5 seconds. To find the acceleration, we can use the formula: acceleration = (final velocity - initial velocity) / time. Since the car is moving with uniform acceleration, we can assume that the initial velocity is 0. The final velocity can be calculated using the formula: final velocity = initial velocity + (acceleration * time). Substituting the values, we get: 700 = 0 + (acceleration * 5). Solving for acceleration, we find that it is equal to 10 m/s^2.Rate this question:
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- 25.
In Highly rarefied gases, the concept loses validity is associated with
- A.
Continum Theory
- B.
Thermodynamic Equilibrium
- C.
Stability
- D.
Macroscopic Approach
Correct Answer
A. Continum TheoryExplanation
The concept of "Highly rarefied gases" refers to gases that are very dilute and have low densities. In such gases, the Continuum Theory, which assumes that the gas can be treated as a continuous medium, loses its validity. This is because at very low densities, the gas molecules are far apart and interactions between them become significant, leading to deviations from the assumptions of the Continuum Theory. Therefore, the concept loses validity in highly rarefied gases.Rate this question:
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- 26.
In Which of the following process the total heat is converted into work
- A.
Reversible Adiabatic Process
- B.
Reversible Isothermal Process
- C.
Reversible Isochoric Process
- D.
Reversible Isoboric Process
Correct Answer
B. Reversible Isothermal ProcessExplanation
In a reversible isothermal process, the total heat is converted into work. This is because in an isothermal process, the temperature remains constant. As a result, the system absorbs heat from the surroundings and converts it into work without any change in temperature. This process is reversible, meaning that it can be reversed to its initial state without any loss or gain of energy. Therefore, the total heat is completely converted into work in a reversible isothermal process.Rate this question:
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- 27.
The vertical load applied to a beam is specified as w(x). The moment distribution, M(x), in this beam can be determined by solving which of these differential equations?
- A.
W = dM/dx
- B.
W = d^2M/dx^2
- C.
W = d^3M/dx^3
- D.
None of the above
Correct Answer
B. W = d^2M/dx^2Explanation
The given equation w = d^2M/dx^2 represents the second derivative of the moment distribution M(x) with respect to x. This equation is known as the equation of equilibrium for a beam under vertical loading. It states that the vertical load applied to the beam (w(x)) is equal to the second derivative of the moment distribution with respect to x. This equation is derived from the equilibrium conditions of forces and moments acting on the beam. Therefore, the correct answer is w = d^2M/dx^2.Rate this question:
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- 28.
A gymnastic beam can be modeled with a 10 cm x 40 cm crosssection and 6 m between its supports. A gymnast lands at the center of this beam with a 1.5 kN force. What is the shear stress on the upper surface of the beam directly below the force of the gymnast?
- A.
0 Kpa
- B.
31 Kpa
- C.
18 Kpa
- D.
40 Kpa
Correct Answer
A. 0 KpaExplanation
The shear stress on the upper surface of the beam directly below the force of the gymnast is 0 Kpa. This is because shear stress is calculated by dividing the force applied perpendicular to the area by the area itself. In this case, the force applied is 1.5 kN and the area is 10 cm x 40 cm. However, since the gymnast lands at the center of the beam, the force is evenly distributed on both sides, resulting in an equal and opposite force canceling each other out. Therefore, the net force is 0, leading to a shear stress of 0 Kpa.Rate this question:
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- 29.
A ridgidly mounted, 3cmdiameter, 1m long, solid circular rod has a 500 N load applied at the free end of the rod and edge of the crosssection. Will this rod fail by buckling if it is made of aluminum (E = 70 GPa, σu = 200 MPa)?
- A.
Yes
- B.
No
- C.
Can't Say
- D.
Not Applicable
Correct Answer
B. NoExplanation
The rod will not fail by buckling because the critical buckling load is greater than the applied load. The critical buckling load can be calculated using the Euler's buckling formula, which states that the critical buckling load is given by P_critical = (Ï€^2 * E * I) / (L^2), where E is the modulus of elasticity, I is the moment of inertia of the cross-section, and L is the length of the rod. Since the diameter and length of the rod are given, we can calculate the moment of inertia and substitute the values into the formula to determine the critical buckling load.Rate this question:
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- 30.
The correct sequence of the given materials in descending order of their weldability is
- A.
Mild steel, Copper, Cast Iron, Al
- B.
Cast iron, Al, Mild steel, Copper
- C.
Copper, Cast iron, Mild steel, Al
- D.
Al, Cast iron, Copper, Mild steel
Correct Answer
A. Mild steel, Copper, Cast Iron, AlExplanation
The correct sequence of the given materials in descending order of their weldability is mild steel, copper, cast iron, and aluminum. Weldability refers to the ease with which a material can be welded. Mild steel is known for its excellent weldability due to its low carbon content and the absence of other alloying elements. Copper also has good weldability as it has a high thermal conductivity and low melting point. Cast iron has lower weldability compared to mild steel and copper due to its high carbon content and brittleness. Aluminum has the lowest weldability among the given materials due to its high thermal conductivity and oxide layer formation during welding.Rate this question:
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- 31.
An elastoplastic material has a yield strength of σy = 100 MPa, modules of elasticity E = 150 GPa, and ultimate strain of 2500 μ. What is the modulus of toughness of this material?
- A.
10.3 KPa
- B.
106 KPa
- C.
301 KPa
- D.
150 Kpa
Correct Answer
A. 10.3 KPaExplanation
The modulus of toughness is a measure of the ability of a material to absorb energy before fracturing. It is calculated by integrating the stress-strain curve up to the point of fracture. In this case, the ultimate strain is given as 2500 μ, which means the material can withstand a strain of 2500 μ before fracturing. The modulus of toughness can be calculated by multiplying the yield strength (σy) by the ultimate strain (εf). Therefore, the modulus of toughness for this material would be 100 MPa * 2500 μ = 250,000 KPa = 250 KPa. Since none of the given options match this value, the correct answer is not available.Rate this question:
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- 32.
In a slider-crank mechanism, lengths of crank and connecting rod are 1 m and 2 m respectively. If the crank rotates with a uniform angular speed of 10 rad/s , the maximum acceleration of the slider (in m/s2) is
- A.
300
- B.
200
- C.
400
- D.
600
Correct Answer
A. 300Explanation
The maximum acceleration of the slider can be calculated using the formula for acceleration in a slider-crank mechanism. The formula is given by a = (ω^2) * r, where ω is the angular speed of the crank and r is the length of the connecting rod. Plugging in the values, we get a = (10^2) * 2 = 100 * 2 = 200 m/s^2. Therefore, the given answer of 300 m/s^2 is incorrect.Rate this question:
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- 33.
The velocity Potential function for a source varies with the distance r as
- A.
1/r
- B.
1/r^2
- C.
E^r
- D.
Ln r
Correct Answer
D. Ln rExplanation
The correct answer is ln r. The velocity potential function for a source is given by ln r, where r represents the distance from the source. This is because the velocity potential is inversely proportional to the distance from the source. The natural logarithm function, ln r, satisfies this condition and provides an accurate representation of the velocity potential for a source.Rate this question:
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- 34.
A Tank is initially empty after sometime Water from height h is falling into the tank with Volume flow rate is Q , the Velocity of the water when it hits the Tank surface is 2 m/s at any instant of time the mass of tank and Water is 250 Kg and Accelaration due to gravity is 10 m/sec^2 . Then Total force (N) resisted by the weighing balance at that instant of time is
- A.
2500 + 2000 Q
- B.
2000 + 2000 Q
- C.
2000 + 2500 Q
- D.
2500 + 2500 Q
Correct Answer
A. 2500 + 2000 QExplanation
The total force resisted by the weighing balance at that instant of time can be calculated using the equation F = mg, where F is the force, m is the mass, and g is the acceleration due to gravity. In this case, the mass of the tank and water is given as 250 kg. Therefore, the force is equal to 250 kg multiplied by 10 m/s^2 (acceleration due to gravity), which gives us 2500 N. Additionally, the velocity of the water when it hits the tank surface is given as 2 m/s. The force due to the water hitting the tank surface can be calculated using the equation F = mv, where m is the mass and v is the velocity. Therefore, the force due to the water hitting the tank surface is equal to 2000 Q N (Q is the volume flow rate). Therefore, the total force resisted by the weighing balance at that instant of time is 2500 + 2000 Q N.Rate this question:
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- 35.
Two pipes of uniform section but different diameters carry water with same flow rate if the both pipe carries same water. Then Which one of the following Observations is true regarding Reynolds number
- A.
Re is large in small pipe
- B.
Re is smaller in the narrower pipe
- C.
Re is same in Both pipe
- D.
Cant' say Due to insufficient Data
Correct Answer
A. Re is large in small pipeExplanation
The Reynolds number is a dimensionless quantity that determines the flow characteristics of a fluid. It is calculated using the fluid velocity, pipe diameter, and fluid properties. In this case, the question states that both pipes carry the same water with the same flow rate. Since the pipes have different diameters, the smaller pipe will have a higher velocity compared to the larger pipe in order to maintain the same flow rate. Since the Reynolds number is directly proportional to the velocity and pipe diameter, and inversely proportional to the fluid viscosity, the smaller pipe will have a larger Reynolds number. Therefore, the statement "Re is large in small pipe" is true.Rate this question:
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- 36.
Which one of thermodynamic Properties is not dependent upon the mass of substance
- A.
Kinectic Energy
- B.
Volume
- C.
Density
- D.
Entropy
Correct Answer
C. DensityExplanation
Density is a thermodynamic property that is independent of the mass of a substance. Density is defined as the ratio of mass to volume, so it is a property that describes how compact or spread out the particles of a substance are. It is not affected by the amount or quantity of the substance, only by the arrangement and spacing of its particles. Therefore, density remains constant regardless of the mass of the substance, making it independent of mass.Rate this question:
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- 37.
The Average in 1-D incompressible fully developed laminar flow between two parallel fixed plates is 4 m/s. Then the maximium velocity of the flow is
- A.
8
- B.
12
- C.
6
- D.
9
Correct Answer
C. 6Explanation
In fully developed laminar flow, the velocity profile is parabolic, with the maximum velocity occurring at the center of the flow. The average velocity is calculated by taking the integral of the velocity profile over the cross-sectional area and dividing it by the area. Since the average velocity is 4 m/s, it means that the velocity at the center of the flow is also 4 m/s. Therefore, the maximum velocity of the flow is 6 m/s, which is twice the average velocity.Rate this question:
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- 38.
The boundary layer thickness is 2mm at a location where the Reynolds number is 1600. if the velocity of the fluid alone is increased by 4 times Then the boundary layer thickness at the same location, in mm will be
- A.
1
- B.
2
- C.
0.5
- D.
1.5
Correct Answer
A. 1Explanation
When the velocity of the fluid is increased by 4 times, the Reynolds number will also increase by 4 times. The boundary layer thickness is directly proportional to the square root of the Reynolds number. Therefore, if the Reynolds number is multiplied by 4, the boundary layer thickness will be multiplied by the square root of 4, which is 2. Hence, the boundary layer thickness at the same location will be 2mm.Rate this question:
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- 39.
In Kinematic Mechanicm having all Turning Pairs, The number of Link is 8 and Closed loop 4 then the Total no of Kinematic Pair is
- A.
12
- B.
11
- C.
13
- D.
10
Correct Answer
B. 11Explanation
In kinematic mechanism, a turning pair is a type of joint that allows relative motion between two links. In this question, it is stated that there are 8 links and 4 closed loops in the mechanism. Each closed loop consists of 2 links connected by a turning pair, so there are a total of 8 turning pairs in the mechanism. However, since each turning pair is counted as 2 kinematic pairs (one for each link it connects), the total number of kinematic pairs is 8 x 2 = 16. However, since there are 4 closed loops, each closed loop has one redundant kinematic pair, so we subtract 4 from the total, resulting in 16 - 4 = 12 kinematic pairs. Therefore, the correct answer is 12, not 11.Rate this question:
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- 40.
The Circular Pitch of pinion whose radius 40 mm is 20. The Angle in Radian Turned by contact Teeth is
- A.
0.5
- B.
0.25
- C.
1
- D.
0.75
Correct Answer
A. 0.5Explanation
The circular pitch of a gear is the distance between corresponding points on adjacent teeth measured on the pitch circle. In this case, the circular pitch of the pinion is 20. The angle in radian turned by contact teeth can be calculated by dividing the circular pitch by the radius of the pinion. Since the radius is 40 mm, the angle is 20/40 = 0.5 radian.Rate this question:
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- 41.
The Transmissibility of dampfree vibration system whose Magnification Factor is 0.03
- A.
0.06
- B.
0.03
- C.
0.09
- D.
0.01
Correct Answer
B. 0.03Explanation
The transmissibility of a dampfree vibration system is a measure of how much the vibration is transmitted from the input to the output. The magnification factor represents the ratio of the output amplitude to the input amplitude. In this case, the magnification factor is 0.03, which means that the output amplitude is 0.03 times the input amplitude. Therefore, the transmissibility of the system is also 0.03.Rate this question:
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- 42.
In Damped Vibrations system The resonance condition is exist. If the Damping factor is 0.25 Then the Magnification Factor of vibratory system is
- A.
1
- B.
0.5
- C.
0.25
- D.
2
Correct Answer
D. 2Explanation
In a damped vibrations system, the resonance condition occurs when the damping factor is equal to the square root of 2 divided by 2, which is approximately 0.707. In this case, the damping factor is given as 0.25, which is less than the resonance condition. Therefore, the magnification factor of the vibratory system will be greater than 1, indicating an amplification of the vibrations. The correct answer is 2.Rate this question:
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- 43.
The two principle stresses are equal in Magnitude and Direction and is Equal to 100 Mpa. Then the Permissible Yield Stress (MPa) in Simple Tension According to Distortion Energy Theory is
- A.
200 MPa
- B.
100 MPa
- C.
150 MPa
- D.
90 Mpa
Correct Answer
B. 100 MPaExplanation
According to the Distortion Energy Theory, the permissible yield stress in simple tension is equal to the magnitude of the two principal stresses divided by the factor of safety. Since the two principal stresses are equal in magnitude and direction and equal to 100 MPa, the permissible yield stress would be 100 MPa.Rate this question:
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- 44.
The Friction Clucthes works on the Uniform Wear Theory and is acting Pressure Equal to P in MPa. If the the outer dia is 2 times of that inner dia. Also if the Area of clutch based on outer dia is K Square meter. Then the Force in (MN)acting on the bearing is
- A.
2PK
- B.
PK
- C.
4PK
- D.
8PK
Correct Answer
D. 8PKExplanation
The force acting on the bearing is 8PK. This can be explained by the Uniform Wear Theory, which states that the pressure acting on the clutch is uniform. The pressure is equal to P in MPa. The area of the clutch based on the outer diameter is K square meters. The force acting on the clutch is equal to the product of the pressure, area, and a constant factor of 8. Therefore, the force acting on the bearing is 8PK.Rate this question:
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- 45.
The stress acting on a element in X and Y direction is 40 MPa and 30 Mpa. Then the Average of maximium and minimium Principle Stress is
- A.
35
- B.
45
- C.
50
- D.
55
Correct Answer
A. 35Explanation
The average of the maximum and minimum principle stress can be calculated by adding the maximum and minimum principle stress values and dividing the sum by 2. In this case, the maximum principle stress is 40 MPa and the minimum principle stress is 30 MPa. Therefore, the average of the maximum and minimum principle stress is (40 + 30) / 2 = 35 MPa.Rate this question:
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- 46.
In a Pelton wheel Turbine Water hits the bucket with the flow rate of 1 Cubic meter and Velocity of Jet Equal to 3 m/s. If the speed ratio is 0.5, Power in KW Developed by Turbine if Whirl component of velocity at Exist is Zero
- A.
1.5
- B.
3
- C.
4.5
- D.
Columbia
- E.
2
Correct Answer
C. 4.5Explanation
The power developed by a Pelton wheel turbine can be calculated using the formula: Power = (Density of water x Flow rate x Velocity of jet x Velocity of jet) / 1000. Given that the flow rate is 1 cubic meter, the velocity of the jet is 3 m/s, and the speed ratio is 0.5, we can calculate the power as follows: Power = (1000 x 1 x 3 x 3 x 0.5) / 1000 = 4.5 kW. Therefore, the correct answer is 4.5.Rate this question:
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- 47.
The condition of stability of governer is stated as
- A.
The rate of increase of controlling force is equal to the rate of increase of radius
- B.
The rate of increase of controlling force must be greater than the rate of increase of radius
- C.
The rate of increase of controlling force must be less than the rate of increase of radius
- D.
None of the above
Correct Answer
B. The rate of increase of controlling force must be greater than the rate of increase of radiusExplanation
The condition of stability of a governor is that the rate of increase of the controlling force must be greater than the rate of increase of the radius. This means that as the radius of the governor increases, the controlling force must increase at a faster rate to maintain stability. If the controlling force increases at a slower rate than the radius, the governor will become unstable and may not be able to regulate the speed or power of the system effectively. Therefore, the correct answer is that the rate of increase of controlling force must be greater than the rate of increase of radius.Rate this question:
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- 48.
Which is the correct statement about cycloidal gears
- A.
The Pressure angle is Constant from the commencement of the engagement to the end of the engagement
- B.
The gears is manufactured with simplicity
- C.
There is no interference in these gears
- D.
Variation in centre distance within limits does not affect the velocity ratio of the two mating gears
Correct Answer
C. There is no interference in these gearsExplanation
Cycloidal gears do not have any interference, which means that the teeth of the gears do not collide or interfere with each other during operation. This is an advantage as it allows for smooth and efficient power transmission without any risk of damage to the gears.Rate this question:
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- 49.
2x+y+z= 0, y-z=0, x+y=0, The system of algebric Equations has
- A.
A unique solution
- B.
No solution
- C.
Infinite number of Solutions
- D.
Five Solutions
Correct Answer
C. Infinite number of SolutionsExplanation
The given system of algebraic equations has an infinite number of solutions because the equations are not independent and can be satisfied by multiple values of x, y, and z. The second equation y-z=0 implies that y=z, and the third equation x+y=0 implies that x=-y. Substituting these values into the first equation 2x+y+z=0, we get 2(-y)+y+y=0, which simplifies to 0=0. This means that any values of y and z that satisfy y=z can be used to satisfy the equations, resulting in an infinite number of solutions.Rate this question:
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- 50.
A Pipe carrying hot fluid and it is desired to reduceing the heat loss. If the two insulating material of Thermal Conductivity 2 K and 4 K are available for lagging a pipe and the radial thickness of each material is same. Then
- A.
Higher thermal conductivity material should be used for inner layer and low thermal conductivity material should be used for outer layer
- B.
Higher thermal conductivity material should be used for outer layer and low thermal conductivity material should be used for inner layer
- C.
Selection of material for any layer is independent on thermal conductivity
- D.
Can't judge due to insufficient data
Correct Answer
B. Higher thermal conductivity material should be used for outer layer and low thermal conductivity material should be used for inner layerExplanation
The higher thermal conductivity material should be used for the outer layer and the lower thermal conductivity material should be used for the inner layer. This is because the outer layer of the insulation will be exposed to the surrounding environment, which is typically at a lower temperature. Using a material with higher thermal conductivity for the outer layer will allow for better heat transfer from the pipe to the surroundings, reducing heat loss. The inner layer, on the other hand, will be in direct contact with the hot fluid inside the pipe. Using a material with lower thermal conductivity for the inner layer will help to minimize heat transfer from the fluid to the surroundings, further reducing heat loss.Rate this question:
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Mar 21, 2023Quiz Edited by
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Feb 28, 2015Quiz Created by
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