1.
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2.
Which of the following systems generate more energy when used in industrial applications?
Correct Answer
A. Hydraulic systems
Explanation
Hydraulic systems generate more energy when used in industrial applications compared to pneumatic systems. This is because hydraulic systems use incompressible fluids to transmit power, which allows for higher force and torque output. In contrast, pneumatic systems use compressed air, which has lower energy density and cannot generate as much power as hydraulic systems. Therefore, hydraulic systems are more suitable for heavy-duty industrial applications that require higher energy output.
3.
Which type of compressor requires a reservoir for compressed air and why?
Correct Answer
B. Reciprocating compressor to avoid pulsating effect
Explanation
A reciprocating compressor requires a reservoir for compressed air to avoid pulsating effect. This is because a reciprocating compressor operates by using a piston to compress air in a cylinder, which creates a pulsating flow of compressed air. By having a reservoir, the pulsations can be absorbed and smoothed out, resulting in a more consistent and continuous flow of compressed air.
4.
Which of the following factors is considered while selecting a compressor?
Correct Answer
B. Volumetric efficiency
Explanation
Volumetric efficiency is considered while selecting a compressor because it measures the actual amount of air that is delivered by the compressor compared to the theoretical amount of air that it should deliver. This factor is important because it determines the efficiency and performance of the compressor. By considering the volumetric efficiency, one can ensure that the compressor is capable of delivering the required amount of air for the specific application.
5.
Where is an inter-cooler connected in a two stage compressor?
Correct Answer
B. Inter-cooler is connected between the two stages of the compressor
Explanation
In a two-stage compressor, an inter-cooler is connected between the two stages of the compressor. This is done to cool down the compressed air between the stages, as the compression process generates heat. By cooling the air, the inter-cooler helps to increase the efficiency and performance of the compressor. It also prevents excessive heat buildup, which can cause damage to the compressor components. Therefore, connecting the inter-cooler between the two stages is the correct placement to optimize the cooling process and ensure proper functioning of the compressor.
6.
Which valve is also known as memory valve?
Correct Answer
B. Double pilot signal valve
Explanation
The double pilot signal valve is also known as the memory valve because it is designed to hold its last position even when the control signal is removed. This allows the valve to "remember" its position and maintain it until a new control signal is received. This feature is useful in applications where maintaining a specific position is important, such as in hydraulic systems or pneumatic control systems.
7.
Which of the following is a gas charged accumulator?
Correct Answer
A. Bladder type
Explanation
A gas charged accumulator is a device used to store energy in the form of pressurized gas. It consists of a bladder or diaphragm that separates the gas and the hydraulic fluid. When the hydraulic system is pressurized, the gas is compressed, and when the system pressure drops, the stored energy is released to provide additional power. The bladder type accumulator is a specific type of gas charged accumulator that uses a flexible bladder to separate the gas and fluid. It is commonly used in hydraulic systems to absorb shocks, dampen pressure fluctuations, and provide emergency power.
8.
Which of the following gas is used in gas charged accumulator?
Correct Answer
B. Nitrogen
Explanation
Gas charged accumulators are commonly used in hydraulic systems to store energy and provide a source of pressure. Nitrogen gas is typically used in gas charged accumulators because it is non-reactive, non-flammable, and readily available. Nitrogen gas also has a high compressibility, allowing it to store and release energy effectively. Oxygen and carbon dioxide are not commonly used in gas charged accumulators due to their reactivity and flammability. Therefore, the correct answer is nitrogen.
9.
Intensifier used in pneumatic systems has output pressure
Correct Answer
B. More than input pressure
Explanation
In pneumatic systems, an intensifier is used to increase the pressure of the output fluid. This means that the output pressure is greater than the input pressure. Therefore, the correct answer is "more than input pressure."
10.
Function of muffler in Pneumatic system is
Correct Answer
B. To Reduce the noise of compressed air
Explanation
The function of a muffler in a pneumatic system is to reduce the noise produced by the compressed air. When air is compressed, it can create a loud and disruptive noise. The muffler is designed to dampen and absorb the sound waves, thereby reducing the noise level. This is important in many applications where a quieter working environment is desired, such as in factories or workshops.
11.
The seals prevents even a minute amount of fluid leakage is called
Correct Answer
A. Positive seal.
Explanation
A positive seal is a type of seal that effectively prevents any fluid leakage, even in very small amounts. It ensures a tight and secure closure, leaving no room for any leakage to occur. This is in contrast to a non-positive seal, which may allow some fluid to leak. Static seals are used when there is no relative motion between the sealing surfaces, while dynamic seals are used when there is relative motion. Therefore, the correct term for a seal that prevents even a minute amount of fluid leakage is a positive seal.
12.
The seals are used between the surfaces of moving hydraulic parts
Correct Answer
D. Dynamic seal
Explanation
A dynamic seal is the correct answer because it is used between the surfaces of moving hydraulic parts. Unlike static seals that are used between stationary components, dynamic seals are designed to prevent leakage and maintain the integrity of the hydraulic system when there is relative motion between the parts. These seals are typically used in applications where there is reciprocating or rotating motion, such as piston seals in hydraulic cylinders or shaft seals in rotary equipment. They are specifically designed to withstand the dynamic forces and pressures involved in these applications and provide an effective barrier against fluid leakage.
13.
Schedule no. of pipe is related to
Correct Answer
C. Wall thickness
Explanation
The schedule number of a pipe is related to its wall thickness. The schedule number is a standard designation that indicates the thickness of the pipe's wall. It is used in various industries to ensure compatibility and proper functioning of pipes in different applications. The higher the schedule number, the thicker the wall of the pipe. Therefore, the correct answer is wall thickness.
14.
Shuttle valve is known as
Correct Answer
C. OR gate valve
Explanation
A shuttle valve is a type of valve that allows fluid to flow from one input port to either of two output ports. It is commonly used in hydraulic systems to control the direction of fluid flow. In this context, it can be considered as an "OR gate valve" because it allows fluid to flow through either of the output ports if there is pressure at one of the input ports. Therefore, the correct answer is "OR gate valve".
15.
When only a portion of the oil is passed through the filter is known as
Correct Answer
D. By pass filter
Explanation
A bypass filter refers to a situation where only a portion of the oil is directed through the filter. This can occur when there is a separate pathway or channel that diverts some of the oil flow away from the main filter. The purpose of a bypass filter is often to provide additional filtration for a smaller portion of the oil, while allowing the majority of the oil to bypass the filter altogether. This can be useful in situations where the full flow of oil would be too much for a single filter to handle, or when a more specialized or finer filtration is required for a smaller portion of the oil.
16.
In hydraulic systems,
Correct Answer
A. The mechanical energy is transferred to the oil and then converted into mechanical energy
Explanation
In hydraulic systems, mechanical energy is transferred to the oil. This is achieved by using a pump to create pressure in the oil, which in turn allows the oil to transmit force and energy to other components of the system. The mechanical energy in the oil is then converted back into mechanical energy when it is used to drive a piston or other mechanical devices. This process allows hydraulic systems to efficiently transmit and control power in various applications.
17.
Which of the following is used as a component in hydraulic power unit?
Correct Answer
C. Valve
Explanation
A valve is used as a component in a hydraulic power unit. Valves are crucial in controlling the flow of fluid in a hydraulic system. They can regulate the pressure, direction, and flow rate of the fluid, allowing for precise control of the system. Without a valve, it would be difficult to control the operation of the hydraulic power unit effectively.
18.
Rotary motion in a hydraulic power unit is achieved by using
Correct Answer
D. None of the above
19.
Accessories used in a hydraulic power unit adjust pressure and are used to generate flow and direction of the fluid
Correct Answer
B. False
Explanation
The statement is false because accessories used in a hydraulic power unit do not adjust pressure or generate flow and direction of the fluid. Accessories in a hydraulic power unit are typically used for monitoring and controlling the system, such as pressure gauges, temperature sensors, control valves, and filters. These accessories help in maintaining the proper functioning and efficiency of the hydraulic system, but they do not directly adjust pressure or generate flow and direction.
20.
Which of the following is used as an accessory in hydraulic power unit?
Correct Answer
D. Reservoir
Explanation
A reservoir is used as an accessory in a hydraulic power unit to store and supply hydraulic fluid to the system. It acts as a storage tank for the hydraulic fluid, ensuring a continuous and reliable supply of fluid to the pumps, valves, and other components of the hydraulic system. The reservoir also helps in cooling the hydraulic fluid and removing any contaminants or air bubbles present in the system. Overall, the reservoir plays a crucial role in maintaining the proper functioning and efficiency of the hydraulic power unit.
21.
Which of the following statements are true?
1. Bell housing connects motor and pump
2. Centrifugal pump is a non-positive displacement pump
3. Centrifugal pumps allow the back flow of fluid from delivery side to the suction side of the pump
4. The function of vent plug used in a reservoir is to flush out oil
Correct Answer
B. 2, 3 and 4
Explanation
Statement 1 is incorrect because the bell housing is a protective cover for the flywheel and clutch assembly, not a connection between the motor and pump. Statement 2 is true because centrifugal pumps are non-positive displacement pumps, meaning they use centrifugal force to move fluid rather than trapping and displacing a fixed amount of fluid. Statement 3 is true because centrifugal pumps do not have valves to prevent backflow, allowing fluid to flow from the delivery side back to the suction side. Statement 4 is true because the vent plug in a reservoir is used to release trapped air and flush out oil contaminants. Therefore, the correct answer is 2, 3, and 4.
22.
Which type of pump is used for lifting water from the ground surface to the top of the building?
Correct Answer
D. All the above
Explanation
All three types of pumps - centrifugal pump, turbine pump, and submersible pump - can be used for lifting water from the ground surface to the top of a building. A centrifugal pump uses centrifugal force to move the water, a turbine pump uses the energy from a rotating impeller to lift the water, and a submersible pump is designed to be submerged in the water and lift it to the desired height. Therefore, all three types of pumps can be used for this purpose.
23.
Pumps used in hydraulic applications are
Correct Answer
D. All the above
Explanation
The correct answer is "all the above" because pumps used in hydraulic applications can be positive displacement pumps, variable displacement pumps, or fixed displacement pumps. Positive displacement pumps deliver a fixed amount of fluid with each stroke, variable displacement pumps can adjust the amount of fluid delivered, and fixed displacement pumps deliver a fixed amount of fluid per revolution. Therefore, all three types of pumps can be used in hydraulic applications depending on the specific requirements and conditions.
24.
What is a positive displacement pump?
Correct Answer
D. All the above
Explanation
A positive displacement pump is a type of pump that operates by trapping a fixed volume of fluid and then displacing it to the delivery side. This means that the oil from the suction side of the pump flows completely to the delivery side, and the volume of fluid discharged cannot return back to the suction side. Therefore, all the given statements are correct and describe the characteristics of a positive displacement pump.
25.
While operating a positive displacement pump,
Correct Answer
C. The shut-off valve should be opened on delivery side
Explanation
When operating a positive displacement pump, it is necessary to open the shut-off valve on the delivery side. This is because positive displacement pumps work by trapping a fixed amount of fluid and then forcing it into the discharge pipe. By opening the shut-off valve on the delivery side, the pump is able to discharge the fluid and maintain a continuous flow. Closing the shut-off valve on the delivery side would prevent the fluid from being discharged and could cause damage to the pump. Therefore, the correct action is to open the shut-off valve on the delivery side.
26.
To actuate double acting cylinder using………….. D.C. valve.
Correct Answer
C. 4/3 D.C. valve
Explanation
A 4/3 D.C. valve is used to actuate a double acting cylinder. This type of valve has four ports and three positions. It allows the control of the flow of fluid to and from the double acting cylinder, enabling the cylinder to move in both directions. The valve can switch between different positions to control the direction of the fluid flow, allowing the cylinder to extend and retract as needed. The other options, 2/2 D.C. valve and 3/2 D.C. valve, do not have the necessary number of ports and positions to actuate a double acting cylinder. Therefore, the correct answer is 4/3 D.C. valve.
27.
When flow control valve with check valve is placed at inlet of the actuator is known as
Correct Answer
B. Meter-in Circuit
Explanation
A flow control valve with a check valve placed at the inlet of the actuator is known as a meter-in circuit. In this circuit, the flow control valve regulates the flow of fluid into the actuator, while the check valve allows the fluid to flow freely in the reverse direction. This configuration ensures that the actuator receives a controlled flow rate, allowing for precise control of the actuator's speed and position.
28.
Which of the circuit is more effective for clamping of component during drilling operation.
Correct Answer
A. Meter-out circuit
Explanation
The meter-out circuit is more effective for clamping of components during drilling operations. In this circuit, the flow control valve is placed on the exhaust side of the cylinder, allowing the air to exhaust freely when the cylinder is retracting. This ensures that the clamping force remains constant and the component is securely held in place during the drilling operation. The other circuits mentioned, such as the bypass circuit and bleed off circuit, may not provide the same level of control and stability in clamping the component.
29.
To divert the pump delivery to the reservoir for the speed control of the actuator is known as……
Correct Answer
C. Bleed off circuit.
Explanation
A bleed off circuit is used to divert the pump delivery to the reservoir in order to control the speed of the actuator. This circuit allows excess fluid to be released from the system, which helps regulate the pressure and flow rate. By bleeding off the excess fluid, the circuit can effectively control the actuator's speed and prevent any potential damage or overloading.
30.
When the return line of the actuator is connected to the pressure line with the help of D.C. valve is known as…….
Correct Answer
D. None of the above
31.
The circuit used during downward movement of actuator under heavy load to prevent its overrunning is called…
Correct Answer
D. Counterbalance circuit
Explanation
A counterbalance circuit is used during the downward movement of an actuator under heavy load to prevent its overrunning. This circuit helps to balance the weight of the load and provides resistance to the downward movement, ensuring that the actuator does not move too quickly or uncontrollably. By using a counterbalance circuit, the actuator can safely lower the load without causing any damage or overrunning.
32.
The circuit used to perform more than two operations in a sequence is known as…..
Correct Answer
A. Sequencing circuit
Explanation
A sequencing circuit is used to perform more than two operations in a sequence. It is designed to control the order and timing of operations in a circuit, ensuring that each operation occurs in the correct sequence. This type of circuit is commonly used in digital systems, where multiple operations need to be performed in a specific order to achieve the desired outcome.
33.
Which method is used for motion synchronization?
Correct Answer
D. All of the above
Explanation
All of the above options (flow divider, rack and pinion arrangement, and mechanical coupling of actuators) are methods used for motion synchronization. Flow dividers are used to distribute hydraulic fluid evenly among multiple actuators, ensuring synchronized motion. Rack and pinion arrangement is a mechanical system that converts rotational motion into linear motion, allowing for synchronized movement. Mechanical coupling of actuators involves connecting multiple actuators together mechanically, enabling them to move in sync. Therefore, all of these methods can be used for motion synchronization.
34.
- What is the maximum operating pressure of Pneumatic system?
Correct Answer
A. 10 bar
Explanation
The maximum operating pressure of a pneumatic system is 10 bar. This means that the system should not be operated at pressures higher than 10 bar to prevent any damage or failure.
35.
A pneumatic symbol is:
Correct Answer
A. Different from a hydraulic symbol used for the same function
Explanation
A pneumatic symbol is different from a hydraulic symbol used for the same function because pneumatic systems use compressed air to transmit and control power, while hydraulic systems use liquid (usually oil) to transmit and control power. Therefore, the symbols used to represent these systems will be different in order to accurately represent the specific components and functions of each system.
36.
Pneumatic systems usually do not exceed:
Correct Answer
A. 1 hp
Explanation
Pneumatic systems typically do not exceed 1 hp because they rely on compressed air to generate power. Compressed air is not as powerful as other energy sources like electricity or fuel, so it is typically used for smaller applications that do not require a lot of power. Therefore, it is unlikely for pneumatic systems to exceed 1 hp in order to ensure efficient and safe operation.
37.
Most hydraulic circuits:
Correct Answer
A. Operate from a central hydraulic power unit
Explanation
Most hydraulic circuits operate from a central hydraulic power unit. This means that multiple hydraulic components, such as cylinders and valves, are connected to a single power unit that generates hydraulic pressure. This central power unit supplies the necessary hydraulic fluid to all the components in the circuit, allowing them to function properly. This centralized system simplifies maintenance and control of the hydraulic circuit, as all components are connected to a single power source.
38.
Hydraulic and pneumatic circuits:
Correct Answer
C. Perform the same with some exceptions
Explanation
Hydraulic and pneumatic circuits generally perform the same way for all functions, but there are some exceptions. While both systems use fluid to transmit power, hydraulic circuits use liquid (usually oil) while pneumatic circuits use compressed air or gas. The main difference is that hydraulic circuits can generate higher forces and are more suitable for heavy-duty applications, while pneumatic circuits are generally used for lighter tasks. Additionally, hydraulic circuits are more resistant to heat and can operate at higher temperatures. Therefore, although the two systems have similarities, there are some variations in their performance depending on the specific function and application.
39.
The lubricator in a pneumatic circuit is the:
Correct Answer
C. Last element in line
Explanation
The lubricator in a pneumatic circuit is the last element in line because it is typically placed after all other components such as valves and actuators. Its purpose is to supply a controlled amount of lubricating oil to the compressed air, ensuring smooth operation of the components and preventing wear and damage. Placing it last allows for efficient distribution of lubrication throughout the entire system, as the air passes through the lubricator before reaching the components.
40.
Series circuits work on both hydraulic and pneumatic actuators.
Correct Answer
B. False
Explanation
Series circuits do not work on both hydraulic and pneumatic actuators. Hydraulic actuators use a liquid, usually oil, to transmit force, while pneumatic actuators use compressed air or gas. In a series circuit, the components are connected in a single path, meaning that if one component fails, the entire circuit will be disrupted. However, hydraulic and pneumatic actuators are typically used in parallel circuits, where multiple actuators can operate independently. Therefore, the statement is false.
41.
When comparing first cost of hydraulic systems to pneumatic systems, generally they are:
Correct Answer
B. Less expensive to purchase
Explanation
Hydraulic systems are generally less expensive to purchase compared to pneumatic systems. This is because hydraulic systems use incompressible fluids to transmit power, which are more efficient and require fewer components. Pneumatic systems, on the other hand, use compressed air which requires additional equipment such as compressors and air storage tanks, making them more expensive. Additionally, hydraulic systems can handle higher pressures and have greater power density, allowing for smaller and more cost-effective components.
42.
Time Delay valve consist of
Correct Answer
C. FCV, Air Reservoir, 3/2 D.C. valve
Explanation
The correct answer is FCV, Air Reservoir, 3/2 D.C. valve. This combination is the most suitable for a time delay valve. The FCV (Flow Control Valve) is used to control the flow rate of the air, while the Air Reservoir stores the compressed air. The 3/2 D.C. valve is a type of directional control valve that has three ports and two positions. This valve is commonly used in pneumatic systems to control the flow of air. Therefore, the combination of FCV, Air Reservoir, and 3/2 D.C. valve is the most appropriate for a time delay valve.
43.
Which of the following is not the application of Hydraulics system
Correct Answer
B. Spray Painting
Explanation
Spray painting is not an application of a hydraulic system. Hydraulics systems are commonly used in heavy machinery such as dumpers, cranes, and backhoe loaders to provide power and control. However, spray painting does not require the use of hydraulics. Instead, it typically relies on compressed air or other methods to propel paint particles onto a surface.
44.
Heavy lifting work is often accomplished by shifting fluids in big machines. The power system of such machines can be described as
Correct Answer
C. Hydraulic
Explanation
The correct answer is hydraulic because hydraulic systems use fluids, typically oil, to transmit power and accomplish heavy lifting work. These systems work by applying force to a fluid, which then transfers the force to different parts of the machine, allowing it to perform tasks such as lifting heavy objects. Hydraulic systems are commonly used in construction equipment, such as cranes and excavators, as well as in industrial machinery. They offer high power and precision, making them suitable for heavy lifting work.
45.
The scientific principle that makes hydraulic systems possible is
Correct Answer
A. Pascal’s principle
Explanation
Pascal's principle is the scientific principle that makes hydraulic systems possible. This principle states that when pressure is applied to a fluid in a closed system, it is transmitted equally in all directions. In a hydraulic system, this principle allows for the transmission of force through a confined fluid, enabling the amplification of force. By applying a small force to a small piston, for example, a larger force can be generated on a larger piston, allowing for the lifting or moving of heavy objects. Boyle's law, Bernoulli's principle, and the fluid flow principle are not directly related to the functioning of hydraulic systems.
46.
Which of the following reasons make water unsuitable to use as a fluid in hydraulic systems?
1. poor lubrication
2. high viscosity
3. more leakage
4. quickly evaporates
Correct Answer
C. 1, 3 and 4
Explanation
Water is unsuitable to use as a fluid in hydraulic systems because it has poor lubrication properties, meaning it does not provide sufficient lubrication to the moving parts of the system. Additionally, water is prone to leakage, which can lead to inefficiencies and potential damage to the system. Lastly, water quickly evaporates, which can result in a loss of fluid and a decrease in system performance. Therefore, options 1, 3, and 4 are the correct reasons that make water unsuitable for use in hydraulic systems.
47.
Which of the following statements are true?
1. low viscosity fluids have higher leakage
2. high viscosity fluids have high pressure drop
3. low viscosity fluids consume more power
4. low viscosity leads to wear of components
Correct Answer
C. 1, 2 and 4
Explanation
Low viscosity fluids have higher leakage because they can easily flow through small gaps and openings. High viscosity fluids have high pressure drop because they resist flow and create more resistance in the system. Low viscosity fluids can lead to wear of components because they have less lubrication properties and can cause increased friction between moving parts.
48.
In industrial applications hydraulic fluids have viscosity grade ranging from
Correct Answer
C. 46 to 68
Explanation
In industrial applications, hydraulic fluids need to have a specific viscosity grade to ensure optimal performance. The viscosity grade determines the fluid's resistance to flow, which is crucial for proper lubrication and efficient operation of hydraulic systems. The viscosity grade range of 46 to 68 is commonly used in industrial applications as it provides a balance between low temperature fluidity and high temperature stability. This range allows the fluid to maintain its viscosity and flow characteristics across a wide range of operating temperatures, making it suitable for various industrial environments.
49.
High viscosity fluids have
Correct Answer
C. Slow operation
Explanation
High viscosity fluids have slow operation because they are thick and resistant to flow. The high resistance to flow results in slower movement of the fluid through pipes or channels, causing the overall operation to be slower compared to fluids with lower viscosity.
50.
What is viscosity index?
Correct Answer
B. Effect of temperature on changes in viscosity
Explanation
Viscosity index refers to the measure of how the viscosity of a fluid changes with temperature. It indicates the fluid's resistance to flow at different temperatures. As temperature increases, the viscosity of most fluids decreases, meaning they become less resistant to flow. The viscosity index helps to determine how much the viscosity of a fluid changes with temperature, which is important in various industries, such as automotive and lubricants, where the performance of fluids under different temperature conditions is crucial.