Angle of deviation vs angle of incidence (i–δ curve)विचलन कोण बनाम आपतन कोण (i–δ वक्र)Angle of deviation vs angle of incidence (i–δ curve)

NCERT Fig 9.22 · Class 12 Physics · Chapter 9 · interactive diagram

Parts and what they mean

• Axes: i (horizontal), δ (vertical) (अक्ष: i (क्षैतिज), δ (ऊर्ध्वाधर)) — Each point is one ray traced through the prism.
• i–δ curve (i–δ वक्र) — δ first falls, reaches a minimum, then rises. Below about 28° the ray cannot get out of face AC (total internal reflection there).
• Minimum deviation Dm (अल्पतम विचलन Dm) — At minimum deviation i = e, r₁ = r₂ = A/2 and the ray inside is parallel to the base. n = sin[(A + Dm)/2] / sin(A/2).
• Two values of i for the same δ (एक ही δ के लिए i के दो मान) — Any δ (except Dm) occurs for two angles of incidence — i and e simply swap, because the ray path can be reversed.

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 9.22. Report a mistake