Monochromatic red light is incident on a double slit, and the interference pattern is viewed on a screen some distance away. Explain how the fringe pattern would change if the red light source is replaced by a blue light source.
Step 1 of 1
is fringe width
is the distance from the slits to screen
d is the separation of the slits
is the wavelength of the light.
The fringe width in young`s experiment is found with
According to the equation above the fringe width depends on the wavelength. The longer the wavelength of the light used, the wider the fringes.
The wave length of the red light is longer than blue light. The fringe width is wider for the red light than blue light.
When the red light is replaced with blue the fringes gets narrower the number of bright dark bands on the screen increases.