Archimedes principle states that when a body is immersed partly or wholly in a fluid, then the liquid exerts an upward force/upthrust/buoyant force on the body which is equal to the weight of the fluid displaced by the body.
Buoyant force-
The buoyant force is given as
Where FB=Buoyant force
= density of the fluid
V= Volume of the solid body immersed in the liquid or Volume of the fluid displaced
So we can write =weight of the fluid displaced
Where m=mass of the fluid displaced