Hydraulic Systems

 

Question 1: Basic Principles

With reference to hydraulic systems, consider the following statements:

1. Pascal’s Law forms the fundamental principle behind hydraulic systems.
2. In a hydraulic system, pressure applied to a fluid is transmitted equally in all directions.
3. Hydraulic systems only work with compressible fluids to maximize force transmission.

Which of the statements given above is/are correct?

A. 1 and 2 only
B. 2 and 3 only
C. 1 and 3 only
D. 1, 2 and 3

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Answer: A. 1 and 2 only

Explanation:

• Statement 1: Correct – Hydraulic systems are based on Pascal’s Law.
• Statement 2: Correct – The law states pressure is transmitted equally in all directions in an incompressible fluid.
• Statement 3: Incorrect – Hydraulic systems require incompressible fluids, not compressible, to ensure force is transmitted without loss.

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🔍 Question 2: Components & Functioning

Which of the following are considered dynamic components of a hydraulic system?

1. Pumps
2. Valves
3. Actuators
4. Pipes
5. Tanks

Select the correct answer using the code below:

A. 1, 2 and 3 only
B. 1, 2, 4 and 5 only
C. 2, 3, 4 and 5 only
D. 1, 2, 3, 4 and 5

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Answer: A. 1, 2 and 3 only

Explanation:

• Pumps, valves, and actuators are the key dynamic components — they control, move, and direct the fluid and generate output.
• Pipes and tanks are static, used for holding and conveying the oil, not actively contributing to energy transfer.

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🔍 Question 3: Application-based

Which of the following are applications of hydraulic systems?

1. Extension and retraction of aircraft landing gears
2. Operation of earth-moving equipment
3. Energy transmission in wind turbines
4. Controlling power flow in electrical transformers

Select the correct answer using the code below:

A. 1 and 2 only
B. 1, 2 and 3 only
C. 1, 2 and 4 only
D. 2, 3 and 4 only

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Answer: B. 1, 2 and 3 only

Explanation:

• Statements 1, 2, and 3: Correct – All are explicitly mentioned in the article as hydraulic applications.
• Statement 4: Incorrect – Electrical transformers do not use hydraulics for controlling power flow; they operate on electromagnetic principles.

Question 4:

Pascal’s law is crucial for the working of which of the following machines?

1. Hydraulic lift
2. Hydraulic press
3. Vacuum pump
4. Hydraulic brake

Select the correct answer using the code given below:

A. 1, 2 and 4 only
B. 1 and 3 only
C. 2, 3 and 4 only
D. 1, 2, 3 and 4

Answer: A. 1, 2 and 4 only

Explanation:

• Hydraulic lift, press, and brake all work on Pascal’s law.
• A vacuum pump works on creating pressure differences, not hydraulic pressure transmission.

Question 5:

Consider the following advantages of hydraulic systems over mechanical systems:

1. Higher energy efficiency
2. Smoother and more precise movements
3. Capability to handle higher loads with smaller components
4. Works well in both mobile and static applications

Which of the above are correct?

A. 1 and 2 only
B. 2, 3 and 4 only
C. 1, 3 and 4 only
D. 1, 2, 3 and 4

Answer: B. 2, 3 and 4 only

Explanation:

• Statement 1 is incorrect – hydraulic systems have only 30–40% efficiency, which is lower than many mechanical/electrical systems.
• The other three are valid advantages of hydraulics.