Question

When a body is immersed in a fluid either wholly or partially, it is lifted up by a force which is equal to the weight of the fluid displaced by the body is known as

• A. Pascal's law
• B. Euler's principle
• C. Reynold's law
• D. Archimede's principle

Hint:

Remember the key fluid principles:
- Archimedes' Principle: Deals with buoyancy. The upward force equals the weight of the displaced fluid.
- Pascal's Law: Deals with pressure transmission in a confined fluid.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
The question provides a statement of a fundamental principle in fluid mechanics and asks for its name.

Step 2: Detailed Explanation:
The statement "a body immersed in a fluid...is lifted up by a force which is equal to the weight of the fluid displaced by the body" is the exact definition of

Archimedes' Principle.
This upward force is called the buoyant force.
Let's review the other options:
-

(A) Pascal's Law: States that a pressure change at any point in a confined incompressible fluid is transmitted throughout the fluid such that the same change occurs everywhere. This is the principle behind hydraulic jacks.
-

(B) Euler's principle/equations: These are fundamental equations of motion for an inviscid (frictionless) fluid flow.
-

(C) Reynold's law/number: The Reynolds number is a dimensionless quantity used to predict fluid flow patterns (laminar vs. turbulent). It's not a law in the same sense.

Step 3: Final Answer:
The statement describes Archimedes' principle.