Question

For a demonstration, a professor uses a razor blade to cut a thin slit in a piece of aluminum foil. When she shines a laser pointer (λ=680nm) through the slit onto a screen 5.5 m away, a diffraction pattern appears. The bright band in the center of the pattern is 7.9 cm wide.What is the width of the slit? answer in mm.

Answer 1

Answer:

$a=0.0947mm$

Explanation:

Given data

λ=680nm

L=5.5m

ω=7.9cm=0.079m

To find

Width of slit a

Solution

As the single slit of width a has a bright central maximum of width:

ω=2λL/a

a=2λL/ω

Substitute the given values

So

$a=\frac{2*680*10^{-9}m*5.5m}{0.079m} \\a=9.47*10^{-5}m\\or\\a=0.0947mm$