Reflection of a plane wave: triangles EAC and BAC are congruent ⇒ i = rसमतल तरंग का परावर्तन: त्रिभुज EAC और BAC सर्वांगसम ⇒ i = rReflection of a plane wave: triangles EAC and BAC are congruent ⇒ i = r

NCERT Fig 10.6 · Class 12 Physics · Chapter 10 · interactive diagram

Parts and what they mean

• Incident wavefront AB (आपतित तरंगाग्र AB) — Plane wavefront meeting the mirror at angle i.
• BC = vτ (BC = vτ) — Distance B travels to reach the mirror in time τ.
• Wavelet from A (radius vτ) (A से तरंगिका (त्रिज्या vτ)) — Same medium, same speed: in time τ it grows to radius AE = BC = vτ.
• AE = vτ (reflected ray) (AE = vτ (परावर्तित किरण)) — AE = BC, AC common, both triangles right-angled ⇒ congruent ⇒ angle i = angle r.
• Reflected wavefront CE (परावर्तित तरंगाग्र CE) — Tangent from C to the wavelet from A.
• Angle of incidence i (आपतन कोण i) — Between the incident ray and the normal.
• Angle of reflection r (परावर्तन कोण r) — Between the reflected ray and the normal; r = i (law of reflection).
• Incident rays (आपतित किरणें) — Perpendicular to AB.
• Reflected ray (परावर्तित किरण) — Perpendicular to the reflected wavefront CE.
• Normal (अभिलंब) — Perpendicular to the mirror at A.
• Reflecting surface MN (परावर्तक पृष्ठ MN) — A plane mirror.

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 10.6. Report a mistake