Medium MCQ +4 / -1 PYQ · JEE Mains 2025

In a Young's double slit experiment, the source is white light. One of the slits is covered by red filter and another by a green filter. In this case:

  1. A <p>there shall be alternate interference fringes of red and green.</p>
  2. B <p>there shall be an interference pattern for red distinct from that for green.</p>
  3. C <p>there shall be an interference pattern, where each fringe's pattern center is green and outer edges is red.</p>
  4. D <p>there shall be no interference fringes.</p> Correct answer

Solution

<p>When white light is used in Young's double slit experiment and one slit is covered by a red filter and the other by a green filter, several effects occur:</p> <p><p><strong>Different Fringe Widths</strong>: Each color will produce fringes of different widths due to their varying wavelengths. This means that red and green will not overlap perfectly.</p></p> <p><p><strong>Color Overlap</strong>: As the fringe patterns develop, some regions will have overlap due to the differing fringe spacings of red and green light. This overlap will create areas where the colors mix, potentially leading to an appearance of intermediate colors.</p></p> <p>Overall, because each color produces its own pattern and these do not align, a clear interference pattern as seen with monochromatic light (a single color) will not be formed. Instead, there will be a complex pattern where the fringes do not distinctly appear as solid bands of red or green due to the overlapping and different fringe widths.</p>

About this question

Subject: Physics · Chapter: Optics · Topic: Reflection and Mirrors

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