Prism Deviation Formula — the NEET Physics formula with its derivation, variables, validity constraints and worked solver.
Prism Deviation Formula Used to calculate the angular deviation of a light ray passing through a triangular prism in geometrical optics. Sum of internal angles r1 and r2 equals the prism angle A. Deviation at first surface is (i - r1) and at second surface is (e - r2). Total deviation delta is the sum of deviations at both surfaces. The ray must refract through two non-parallel surfaces of the prism. Assumes the prism is surrounded by a medium of lower refractive index, typically air. Thinking deviation is directly proportional to the angle of incidence. Confusing the prism angle A with the angle of refraction. Assuming i is always equal to e for every deviation.