WAVE OPTICS — Physics STD 12 Science — Question

→It is very easy to see the single-slit diffraction pattern for oneself.
→The equipment needed can be found in most homes-two razor blades and one clear glass electric bulb preferably with a straight filament.
→One has to hold two blades so that the edges are parallel and have a narrow slit in between. This is easily done using the thumb and forefingers (fig.)
→Keep the slit parallel to the filament, right in front of the eye. Use the spectacles if you normally do. With slight adjustment of the width of the slit and the parallelism of the edges, the pattern should be seen with its bright and dark bands.
→Since the position of all the bands (except the central one) depends on wavelength, they will show some colours.
→Using a filter for red or blue will make the fringes clearer. With both filters available, the wider fringes for red compared to blue can be seen.
→Another example :
→In case of a dark room, where there is some light entering from outside, if the door is kept slightly open, the diffraction pattern can be seen on the tiles.