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 1

Answer:

width of slit(a)≅ 0.1mm

Explanation:

Wave length of laser pointer =λ = 685 nm

Distance between screen and slit = L = 5.5 m

Width of bright band = W=8.0cm=0.08m

width of slit=a

recall the formula;

W=(2λL)/a

a=2λL/W

a=(2 *685*10⁻⁹*5.5m)/0.08m

a=7535*10⁻⁹/0.08

a=94187.5 *10⁻⁹

a=0.0000941875m

a=0.0941875mm

a≅0.1mm

Answer 2

Answer:

The wide of silt is a=93.5×10⁻⁶m

Explanation:

Given data

Wavelength λ=680 nm

Length L=5.5 m

Width w=8.0 cm

To find

Width of slit a

Solution

A single slit of width a has a bright central maximum of width

ω=2λL/a

a=2λL/ω

Substitute the given values

$a=\frac{2*(680*10^{-9}m)5.5m}{0.08m} \\a=93.5*10^{-6}m$

The wide of silt is a=93.5×10⁻⁶m