Question

Interference was observed in interference chamber, when 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 central bright band
• C. interference with central dark band
• D. interference in which breadth of the fringe will be slightly increased

Answer 1

The correct option is D interference in which breadth of the fringe will be slightly increased

As the chamber is evacuated the wavelength of the light increases slightly. Thus as the fringe width is directly proportional to wavelength the fringe width increases.