Correct Option
The correct option isBuoyancy
Explanation
When a body is immersed wholly or partially in a fluid (liquid or gas), it experiences an upward force exerted by the fluid. This phenomenon is governed by Archimedes' Principle and arises due to the increase in fluid pressure with depth.
Detailed Analysis
- Gravitation: This is the force of attraction exerted by the Earth on the body, pulling it downwards towards the center of the Earth. It is responsible for the weight of the body, not the upward force.
- Buoyancy: This is the upward force exerted by a fluid on an immersed object. It opposes the weight of the object and is responsible for the apparent loss of weight of objects in fluids. This force is also known as upthrust.
- Pressure: While the buoyant force is caused by the difference in pressure acting on the top and bottom surfaces of the object, pressure itself is defined as force per unit area. It is the mechanism, but the specific upward force resulting from it is termed buoyancy.
- Surface Tension Surface Tension: This is a property of the liquid surface that allows it to resist an external force, due to the cohesive nature of water molecules. It acts along the surface plane and is not the bulk upward force experienced by a submerged body.
Key Takeaway: The upward force exerted by a fluid on an object immersed in it is called Buoyancy or Upthrust. It depends on the density of the fluid and the volume of the object immersed.