Pascals Law and its Application - Definition, Formula, Applications, FAQs

Edited By Vishal kumar | Updated on Sep 24, 2024 01:08 PM IST

What is Pascal law Class 11? Define Pascal law and State Pascal’s Law and its Application:

This law was given by the famous French mathematician and philosopher Blaise Pascal in 1647.
The law states that the pressure exerted on other relaxing liquids is the same in all directions.
Whenever external pressure is applied to any part of the liquid contained in a vessel, it is transmitted continuously and evenly in all directions.
Hydraulic power equipment operates on the basis of this rule.

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Pascals Law and its Application - Definition, Formula, Applications, FAQs

Pascal Law Definition

"Stable external pressure applied to a closed fluid is evenly distributed throughout the fluid in all directions." is known as pascal's law.

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Pascal’s law formula

The Pascal law formula shows the relationship between pressure, force exerted and the area of communication i.e.,

P = F/A

Where, P = Pressure, F = Force and A = Contact area

Let’s understand the practical principle of Pascal’s law

for pascal law with an example,

The Pressure Of 2000 Pa Is transmitted to the whole column Of the liquid By inserting the piston. If the piston has an area of 0.1 square meters, What is the force applied?

We can calculate the amount of energy using the pascal law formula.

F = PA

Here,

P = 2000

A = 0.1 m²

After entering the values, we arrive at Force F = 200 N.

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Applications of Pascal law

1. fluid Lift

It has many applications in everyday life. Many devices, such as hydraulic lifting and pressure brakes, are based on Pascal's law. The liquid is used to transfer pressure to all these devices. In a hydraulic lift, the two pistons are separated by a space filled with liquid. The cross-section piston at the small cross A is used to apply force F directly to that liquid. The pressure P = F / A is transferred across the liquid to a larger cylinder fitted with a large area piston B, resulting in a higher force of (P × B. ). Platform B can be moved up or down. Therefore, the force used is increased by the B / A factor

Also Read:

2. Brake fluid

In automobiles, pressure brakes also serve the same purpose. When using less force on the foot, the master piston moves inside the master cylinder, and the resulting pressure is transferred by the oil brakes to form a larger area piston. A high force was then applied to the piston and was pulled down, stretching the braces on the brake line. As a result, the small force at the base produces excessive force returning to the wheel. The main advantage of the system is that the pressure, which is stopped by pressing the pedal, is transmitted evenly across all cylinders, attached to four wheels to make the braking effort equal to all the wheels.

3. Depth of pressure in depth

where P1 is pressure at 1 and P2 is pressure a P2;

Consider resting liquid in a container. In the figure above point 1 height h from point 2. P₁ and P₂ mean pressure on points 1 and 2 respectively. Think of a liquid object with a base A and a height h. As the liquid rests, the next horizontal force must be zero and the vertical force to measure the weight of the object. The force operates vertically, due to the upper and lower water pressure (P₁A) working at the bottom and the lower (P₂A) working at the top. If mg is the weight of the liquid in the cylinder then we can say,

(P₂ -P₁) A = mg

Now, if ρ is the density of the liquid then the mass of the liquid will be

m = ρV = ρhA

(P₂ -P₁) = ρgh

The pressure difference depends on

The vertical distance between points (1 and 2),

The amount of water fluid weight

Acceleration due to gravity g.

If point 1 in question is transferred to the surface of the liquid (say, water), open to the atmosphere, P₁ can be replaced by atmospheric pressure (P_a) and we can add P₂ to P.

P = P_a + ρgh

Also check-

NCERT Physics Notes:

Frequently Asked Questions (FAQs)

1. What is Pascal's law?

According to Pascal's law, "Stable external pressure applied to a closed fluid is still distributed or evenly distributed throughout the fluid in all directions."

2. What is the application of the Pascal law?

Hydraulic lift functions according to the Pascal Act.

3. Does Pascal's law apply to gas?

Pascal's law applies to gas. Pascal's law is also known as pascal’s principle of the transfer of pressure (whether water or gas).

4. Who mentioned Pascal's law?

French mathematician Blaise Pascal enacted Pascal's law in 1653.

5. What is the purpose of the Pascal law?

Pascal's law states that pressure applied to a closed fluid will be transferred without a change in the size of the entire liquid and the walls of the vessel. The pressure at any time in the liquid is equal on all sides.