Youngs double slit Experiment

Question

The following apparatus is used to investigate the light interference using a double slit.

The distance, y, between the slits and the screen can be adjusted. The slit width, S, can also be adjusted. Sam tests two different wavelength: 500nm and 600nm. Explain TWO methods of keeping the distance between maxima A and B constant in both tests.

Answer 1

fringe width = Wavelength * Distance between screen and two slits (y)/ Separation between two slits

To keep fringe width same ,If wave length increases y should be decreased

If y is not changed and wave increases then separation between the two slits should increase to keep fringe width same