- 602

- 0

**Width of Slit....HeLP on setup Please!!**

**1. Homework Statement**

A helium-neon laser (λ=590 nm) illuminates a single slit and is observed on a screen 1.7 m behind the slit. The distance between the first and second minima in the diffraction pattern is 6.78 mm. What is the width (in mm) of the slit?

**2. Homework Equations**

**3. The Attempt at a Solution**

I think I am supposed to use the equation....

W = 2tL/a

t = wavelength

t = 0.00000059 m

L = 1.7 m

a = .00678 m

but that gets me 0.2956 mm

If I divide that by 2 I get the right answer so I am a little confused on my setup