Two polaroids: I = I₀ cos²θ (Malus’ law)दो पोलेरॉइड: I = I₀ cos²θ (मैलस का नियम)Two polaroids: I = I₀ cos²θ (Malus’ law)
NCERT Fig 10.18 · Class 12 Physics · Chapter 10 · interactive diagram
Read Chapter 10 with this diagramइस डायग्राम के साथ अध्याय 10 पढ़ेंIs diagram ke saath Ch 10 padhiyeAll Physics diagramsसभी भौतिकी डायग्रामSaare Physics diagrams
Parts and what they mean
- Unpolarised light, intensity I (अध्रुवित प्रकाश, तीव्रता I) — From a lamp or the Sun: E vibrates in all directions ⊥ the beam.
- First polaroid P₁ (पहला पोलेरॉइड P₁) — Passes only the E-component along its pass-axis (the line drawn). Output intensity I/2, whatever the orientation of P₁.
- Linearly polarised light, I₀ = I/2 (रैखिकतः ध्रुवित प्रकाश, I₀ = I/2) — E now vibrates only along the pass-axis of P₁.
- Second polaroid P₂ (दूसरा पोलेरॉइड P₂) — Its pass-axis is at angle θ to that of P₁: only E cos θ gets through.
- Angle θ between pass-axes (पारित-अक्षों के बीच कोण θ) — θ = 0 → full I₀; θ = 90° (crossed) → zero.
- Transmitted light I₀ cos²θ (पारगमित प्रकाश I₀ cos²θ) — Amplitude E cos θ ⇒ intensity ∝ (E cos θ)² ⇒ I = I₀ cos²θ (Malus’ law).
- Malus’ law graph (मैलस नियम का ग्राफ़) — Two maxima and two minima as P₂ turns through 360° (shown: 0° to 180°).
Original diagram drawn by Simple Learning Hub, based on NCERT Fig 10.18. Report a mistake