JEE Main 2024 Physics question
In Young's double slit experiment, monochromatic light of wavelength 5000 Å is used. The slits are 1.0 mm apart and screen is placed at 1.0 m away from slits. The distance from the centre of the screen where intensity becomes half of the maximum intensity for the first time is × m.
Answer: 125
Solution
I = I₀cos²(Δφ/2) = I₀/2 ⇒ Δφ = π/2; y = λD/(4d) = 5 × 10⁻⁷ × 1/(4 × 10⁻³) = 125 × 10⁻⁶ m.