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The ratio of intensities at two points P and Q on the screen in a Young's double slit experiment where phase difference between two waves of same amplitude are π/3 and π/2, respectively are

Asked in JEE Main 10th April 2nd Shift 2023 · Intensity and coherent sources

• (1) 1 : 3
• (2) 3 : 2
• (3) 2 : 3
• (4) 3 : 1

Step-by-step solution

Why the other options are wrong

• (1) Uses cos²φ at P (cos² 60° = 1/4) and cos² 30° = 3/4 for Q, mixing up the two phases.
• (3) Inverts the ratio.
• (4) Pairs cos² 30° = 3/4 with cos² 60° = 1/4 instead of cos² 45° = 1/2.

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