Refraction and reflection at an interface (Snell’s law)अंतरापृष्ठ पर अपवर्तन और परावर्तन (स्नेल का नियम)Refraction and reflection at an interface (Snell’s law)

NCERT Fig 9.8 · Class 12 Physics · Chapter 9 · interactive diagram

Parts and what they mean

• Medium 1 (rarer here) (माध्यम 1 (यहाँ विरल)) — The medium the light comes from.
• Medium 2 (denser here) (माध्यम 2 (यहाँ सघन)) — Optically denser (n₂₁ > 1), so the ray bends towards the normal: r < i.
• Normal (अभिलंब) — Line perpendicular to the interface at the point of incidence. All angles are measured from it.
• Incident ray (आपतित किरण) — Incident ray, normal and refracted ray all lie in one plane (first law).
• Reflected ray (partial) (परावर्तित किरण (आंशिक)) — A part of the light is always reflected, at angle i.
• Refracted ray (अपवर्तित किरण) — Traced with Snell’s law: sin r = sin i / n₂₁.
• Angle of incidence i (आपतन कोण i) — Between the incident ray and the normal (not the surface).
• Angle of reflection = i (परावर्तन कोण = i) — Law of reflection.
• Angle of refraction r (अपवर्तन कोण r) — Between the refracted ray and the normal.

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 9.8. Report a mistake