Question

In the Young’s double-slit experiment, the intensity of light at a point on the screen where the path difference is λ/K (where λ is the wavelength of light used). The intensity at a point where the path difference is λ/4 will be:

• A. \(K\)
• B. \(K/4\)
• C. \(K/2\)
• D. Zero

Hint:

In YDSE: I ∝ cos²((πΔ)/(λ)) Half-path differences give half of maximum intensity.

Answer 1

The Correct Option is C

Step 1: Intensity in YDSE: I = 4I₀cos²((πΔ)/(λ))
Step 2: At centre (Δ=0): Imax=4I₀=K
Step 3: For Δ=λ/4: I=4I₀cos²((π)/(4)) =4I₀((1)/(2))=2I₀
Step 4: Hence, I=(K)/(2)