JEE Advanced2014PhysicsWave OpticsActual
A light source, which emits two wavelengths λ 1 = 400 n m and λ 2 = 600 n m , is used in a Young's double slit experiment. If recorded fringe widths for λ 1 and λ 2 are β 1 and β 2 and the number of fringes for them within a distance y on one side of the central maximum are m 1 and m 2 , respectively, then
Options
- Aβ 2 > β 1
- Bm 1 > m 2
- CFrom the central maximum, 3 r d maximum of λ 2 overlaps with 5 t h minimum of λ 1
- DThe angular separation of fringes for λ 1 is greater than λ 2
Correct answer
A. β 2 > β 1
Step-by-step solution
β = D λ d ∵ λ 2 > λ 1 ⇒ β 2 > β 1 Also m 1 β 1 = m 2 β 2 ⇒ m 1 > m 2 Also 3 D d 600 n m = 2 × 5 - 1 D 2 d 400 n m Angular width θ = λ d