Wave Optics - Result Question 3

3. Interference was observed in interference chamber where air was present, now the chamber is evacuated, and if the same light is used, a careful observer will see

[1993]

(a) no interference

(b) interference with brighter bands

(c) interference with dark bands

(d) interference fringe with larger width

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Answer:

Correct Answer: 3. (d)

Solution:

  1. (d) In vaccum, $\lambda$ increases very slightly compared to that in air. As $\beta \propto \lambda$, therefore, width of interference fringe increases slightly.