JEE Main201910 Jan 2019Evening ShiftPhysicsWave OpticsActual
Consider a Young's double slit experiment as shown in figure. What should be the slit separation d in terms of wavelength λ such that the first minima occurs directly in front of the slit ( S 1 ) ?
Options
- Aλ 5 - 2
- Bλ 2 5 - 2
- Cλ 2 5 - 2
- Dλ 5 - 2
Correct answer
C. λ 2 5 - 2
Step-by-step solution
Path diff. in front of a slit on screen ∆ = 5 d - 2 d = 2 n - 1 λ 2   (for minima) For 1 s t minima n = 1 d 5 - 2 = λ 2 d = λ 2 5 - 2