How Far Apart Are the Minima in Young's Single Slit Experiment?

[stryker123]

for those of you that are familiar with Young's Single slit experiment, I am having trouble determining how far apart the minima are. The problem is as follows: one shines a laser with wavelength lambda=650nm through a single slit of width a=.04mm onto a screen 10m away. How far apart are the minima? I know that sin[theta]= lambda/a. However, does "a" have to be in meters? nanometers? or millimeters?

 

[hage567]

lambda and a must be expressed in the same units, so that the ratio will make sense. But in this case it doesn't really matter if it's nm, mm or m, since the ratio will come out the same no matter what. But I would say it is best to convert everything to meters, so you don't forget somewhere along the line when it does matter.

Can you show your calculation?