Archimedes Principle — the NEET Physics formula with its derivation, variables, validity constraints and worked solver.
Archimedes' Principle Applies to any object partially or wholly immersed in a fluid (liquid or gas) at rest (hydrostatics). Consider a fluid element at rest. Pressure increases with depth: P = rho g h. Calculate the net force due to pressure difference between the bottom and top surfaces of the submerged volume. F net = (P bottom A) - (P top A). Substitute P = rho g h yields F net = rho g (h bottom - h top) A. Recognize that (h bottom - h top) A is the Volume (V). Result is F b = rho V g. Fluid must be incompressible for constant density assumption. Object must be at least partially submerged. System implies a gravitational field (or equivalent acceleration). Believing the density of the object determines the buoyant force magnitude (it determines floating/sinking, but the force itself depends on fluid density). Using the total volume of the object instead of the submerged (displaced) volume for floating objects. Thinking buoyant force increases with depth for an incompressible fluid (it remains constant once fully submerged).