Question

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

• A. no interference
• B. interference with brighter bands
• C. interference with dark bands
• D. interference with larger width

Answer 1

Answer: (D)

interference with larger width

Answer 2

In vacuum, $\lambda$ increases very slightly compared
to that in air. As $\beta \propto \lambda$ therefore, width of

interference fringe increases slightly.