Question

Monochromatic light with wavelength 490 nm passes through a circular aperture, and a diffraction pattern is observed on a screen that is 1.20 m from the aperture. If the distance on the screen between the first and second dark rings is 1.65 mm, what is the diameter of the aperture?

Answer 1

Answer:

d = 3.56 x 10⁻⁴ m = 0.356 mm

Explanation:

The diameter of the aperture can be found using the following formula:

$y = \frac{\lambda L}{d}\\\\d = \frac{\lambda L}{y}$

where,

y = distance between dark rings = 1.65 mm = 1.65 x 10⁻³ m

λ = wavelength = 490 nm = 4.9 x 10⁻⁷ m

L = distance between screen and aperture = 1.2 m

d = diameter of aperture = ?

Therefore,

$d = \frac{(4.9\ x\ 10^{-7}\ m)(1.2\ m)}{1.65\ x\ 10^{-3}\ m}$

d = 3.56 x 10⁻⁴ m = 0.356 mm