Question

Two sources of light of wavelength 710 nm are 9 m away from a pinhole of diameter 1 mm. How far apart must the sources be for their diffraction patterns to be resolved by Rayleigh's criterion? answer in mm unit

Answer 1

Answer:

7.8 mm

Explanation:

Wavelength = λ = 710 nm = 710×10⁻⁹ m

Distance between light sources =  L = 9 m

Diameter of pinhole = d = 1 mm = 1×10⁻³ m

Rayleigh Criterion

$D=1.22\frac{L\lambda}{d}\\\Rightarrow D=1.22\frac{9\times 710\times 10^{-9}}{1\times 10^{-3}}\\\Rightarrow D=0.0077\ m=7.8\ mm$

Distance between difraction pattern is 7.8 mm.