Question

In double slit experiment, when interference pattern due to whitelight is observed by an observer through a transparent glass of green colour, he finds black and green bright fringes. If green glass is replaced by violet colour glass, then:

• A. No interference pattern will appear
• B. Bright violet fringes will appear to be of smaller width than green fringes
• C. Bright violet fringes will appear to be of more width than green fringes
• D. Bright fringes will be produced of the same width as that of green fringes

Answer 1

Answer: (B)

Bright violet fringes will appear to be of smaller width than green fringes

Fringe width $=\frac{\lambda D}{d}$
As the wavelength of violet light is less than the green light the fringe width decreases.
Hence option B is correct.