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 8.0 cm wide. What is the width of the slit? answer in mm.

Answer 1

width of the slit = a = 0.0935 mm

Step-by-step explanation:

width of central maximum for single slit diffraction is:

`w=(2 \lambda L)/(a)` ----- (1)

Distance between source and screen = L = 5.5 m

Width of bright band = w = 8 cm

= 0.08 m

λ = 680 nm

Width of the slit = a = ?

Arranging (1) for a

`a=(2 \lambda L)/(w)`

`a=(2 (680 * 10^(-9))(  5.5))/(.08)\\a = 93.5 \mu m`

a = 0.0935 mm