Central Maximum/Diffraction Question

[wilson_chem90]

a) A light with a wavelength of 500 nm illuminates two narrow slits that are 0.10 mm apart. If the viewing screen is 1.20 m from the slits, calculate the distance between each maxima.

b) How far would the fourth maximum be from the central maximum?


Relevant equations:
y1 = L x wavelength / w

The attempt at a solution:

a) y1 = L x wavelength / w
= (1.2m)(500 x 10^-9 m) / (1.0 x 10^-4 m)
= 0.006 m

0.006 m x 2 = 0.012 m

so the distance between each maximum is 1.2 x 10^-2 m

b) 4 x (1.2 x 10^-2 m)
= 0.048
= 4.8 x 10^-2 m

I'm not sure if this is correct, can someone please confirm or add any suggestions? thanks

 

[Delphi51]

It isn't perfectly clear what "distance between each maxima" is.
I would say it is the .006 m you found for the distance from the bright central maximum to the first order maximum. And I would multiply .006 by 4 to get part (b).