Interference fringes on the screen and the intensity I = 4I₀ cos²(πxd/λD)पर्दे पर व्यतिकरण फ्रिंज और तीव्रता I = 4I₀ cos²(πxd/λD)Interference fringes on the screen and the intensity I = 4I₀ cos²(πxd/λD)

NCERT Fig 10.13 · Class 12 Physics · Chapter 10 · interactive diagram

Parts and what they mean

• Fringes (bright and dark bands) (फ्रिंज (दीप्त और अदीप्त पट्टियाँ)) — Equally spaced bright and dark bands (computed from the formula).
• Central bright fringe (केंद्रीय दीप्त फ्रिंज) — At x = 0 the path difference is zero.
• First bright fringe (पहला दीप्त फ्रिंज) — Bright fringes at xₙ = nλD/d (n = 0, ±1, ±2, …).
• Dark fringe (अदीप्त फ्रिंज) — Dark fringes at xₙ = (n + ½)λD/d: here I = 0.
• Fringe width β (फ्रिंज चौड़ाई β) — β = xₙ₊₁ − xₙ = λD/d — the same for bright and dark fringes. Bigger λ or D, or smaller d → wider fringes.
• Intensity curve (तीव्रता वक्र) — I = 4I₀ cos²(φ/2) with φ = 2πxd/(λD). Maxima 4I₀, minima 0; the average is 2I₀ — energy is only redistributed.

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 10.13. Report a mistake