Bright Fringes (Intro to Quantum Physics Qestion?)

megaoka

1. The problem statement, all variables and given/known data
The distance between two slits is 0.05mm and the distance to the screen is 2.5m. What is the spacing between the central bright fringe and the first-order fringe? Use yellow light with a wavelength of 580nm


2. Relevant equations
x_m=mλL/d


3. The attempt at a solution
L=0.5mm d=2.5m λ=580nm
x_m=(1)(580x10^-9)/(.5x10^-3) = .00116m
(all the numbers were converted to meters)

Whenever I plug these problems in, I get a strange answer that isn't anywhere near the multiple choice answers. What am I doing wrong?

Multiple choice answer possibilities:

I don't want the answer, I want to know what I did wrong here. If you get the right answer, please help!
Cheers,
~a distressed AP student

dx

Hi megoka,

You mixed up L and d. L is the distance to the screen 2.5 m, and d is the space between the slits 0.05 mm.

megaoka

d=0.5mm L=2.5m λ=580nm
xm=mλL/d

x=(1)(580x10^-9)(2.5)/(0.5x10^-3)=.0029
Okay!

Thanks! I got my answer.