When a compact disc is illuminated by a source of white light,coloured 'lanes' are observed. This is due to

$A$ diffraction pattern is formed by blue light. If the blue light is replaced by yellow light, then . . . . . . .

$A$ narrow slit of width $2 \ mm$ is illuminated with a monochromatic light of wavelength $500 \ nm$. If the distance between the slit and the screen is $1 \ m$,then the first minima are separated by a distance of: (in $mm$)

In order to see diffraction,the thickness of the film must be of the order of:

$A$ slit of width $a$ is illuminated by monochromatic light of wavelength $650 \ nm$. The value of the slit width $a$ when the first minimum is formed at a diffraction angle of $30^\circ$ is:

The phenomenon of diffraction of light was discovered by