JEE Main 2025 Apr 8 Shift 2, Physics Q18: Young’s Double Slit Experiment
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
- A
There shall be an interference pattern for red distinct from that for green.
- B
There shall be no interference fringes.
- C
There shall be alternate interference fringes of red and green.
- D
There shall be an interference pattern, where each fringe's pattern center is green and outer edges is red.
Sustained interference requires the two interfering waves to be coherent, meaning they must maintain a fixed phase relationship over time.
Coherent waves in an optical interference experiment arise when a single source is split into two paths; the red and green filters, however, transmit different, uncorrelated frequency components of the incoming light.
Light transmitted through the red filter and light transmitted through the green filter therefore have different frequencies and no fixed phase relationship, so they cannot interfere to form stable fringes.
The screen instead shows a smooth overlap of independent red and green illumination with no interference pattern, matching option (2).
Concept behind this question
Young’s Double Slit ExperimentNotes, formulas and examples →More previous year questions on Young’s Double Slit Experiment
Practice more Physics
Concept-wise practice with instant solutions on Fundamenthol.
Start practicing →