A screen with three equally spaced slits of the width b and separation a is illuminated at normal incidence with monochromatic light with wavelength lambda. A diffraction pattern is obtained at a distance L on another screen positioned behind the screen with the slits. Calculate and compare the distance between the diffraction maxima with numbers m and m+1 for the cases when either the middle or one of the side slits is blocked. Assume a>>m*lambda
The Attempt at a Solution
Im not entirely sure what it is asking me to do but I started by finding the equations I wanted to use then figured the separation for blocking the middle would be 2a+b and the separation for blocking one of the side slits would just be a.
Then I wrote the two cases up and took the difference between the Y at m=2 and m=1 for both. With no values given I'm not sure where to go next just with algebra, I subbed in some values of
a=300 micron b = 10micron L = 10m lambda = 500nm
and got 0.0082m distance in the first case and 0.017m in the second case but Im not sure this is what I'm being asked to do.