Lateral shift through a glass slabकाँच की पट्टिका से पार्श्विक विस्थापनLateral shift through a glass slab

NCERT Fig 9.9 · Class 12 Physics · Chapter 9 · interactive diagram

Parts and what they mean

• Parallel-sided glass slab (समांतर फलकों वाली काँच की पट्टिका) — Two parallel faces: air → glass, then glass → air.
• Normals (अभिलंब) — Drawn at each point of incidence.
• Incident ray (आपतित किरण) — Enters at angle i₁.
• Ray inside the glass (काँच के अंदर किरण) — Bent towards the normal (r₁ < i₁). Because the faces are parallel, it meets the second face at i₂ = r₁.
• Emergent ray (निर्गत किरण) — Leaves at r₂ = i₁, so it is parallel to the incident ray: no deviation, only a sideways shift.
• Original direction (continued) (मूल दिशा (बढ़ाई गई)) — Where the ray would have gone without the slab.
• Lateral shift d (पार्श्विक विस्थापन d) — Perpendicular distance between the incident and emergent directions: d = t sin(i₁ − r₁)/cos r₁ (t = thickness). Grows with thickness and with i.
• i₁ (i₁) — Angle of incidence at the first face.
• r₁ (r₁) — Angle of refraction at the first face.
• i₂ = r₁ (i₂ = r₁) — Angle of incidence at the second face (alternate angles).
• r₂ = i₁ (r₂ = i₁) — Angle of emergence — equal to i₁.

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 9.9. Report a mistake