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Question 20244
JEE Physics · Hard

Electromagnetic Waves and Wave Optics: YDSE — Path Difference with Source Offset MCQ

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YDSE — Path Difference with Source OffsetHardQuestion 20244

Question

In YDSE, the source S is moved a distance y perpendicular to the line joining the slits. The central maximum shifts:
  1. A
    In the same direction as S
  2. B
    Opposite to the direction of S
    Correct
  3. C
    There is no shift
  4. D
    Depends on wavelength

Correct answer

Opposite to the direction of S

Explanation

When S moves up, the path from S to S₁ (lower slit) increases relative to S₂ (upper slit). S₂ now has the shorter total path to the original central max location. The fringe pattern shifts downward (opposite to S's upward motion) to restore equal total path lengths.

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