The upward force exerted on a body by the fluid in which it is submerged, is called upthrust or buoyant force.

Archimedes' principle states that : "The upward buoyant force that is exerted on a body immersed in a fluid, whether fully or partially submerged, is equal to the volume of the fluid that the body displaces."

A fluid exerts an upward force on a body immersed in it, which is called as ___.

Prove that the loss in weight of a body when immersed wholly or partially in a liquid is equal to the buoyant force (or upthrust) and this loss is because of the difference in pressure exerted by liquid on the upper and lower surfaces of the submerged part of the body.