Question

1/ Explain how the aperture geometry relates to the diffraction pattern.

2/ Predict how changing the wavelength or aperture size affects the diffraction pattern.

Answer 1

1) aperture geometry i.e., shape and size of aperture

shape of aperture if it is slit (like striaght line) like then the diffraction pattern is a straight lines with dark and bright lines.

if it is a circular aperture then the central circle followed by alternate dark and bright rings. all this rings are concentric with cengtral ring.

if it s a striaght edge then the diffraction pattern is alternate dark and brigt bands with varying intensities.

size of the aperture if the aperture size is small then diffraction bands are clear and distinguished. if the size of the aerture is increasing and its size is larger compared to wavelength of light diffraction pattern does not form.

2) d sin ( theta) = n* wave length

where d is size of the slit

if size of the slit is small then for the same wave length and position the order of diffraction pattern n is also small, i.e., more number of orders can be formed on the screnn. i.e., a clear diffraction pattern.

if wave length is increased the order is small for the same location, wave length is more the order is more.