Question

Consider a beam of light with intensity I0.

Imagine the beam passes through two slits 1.50 μm apart and is shined on a screen 55.0 cm from the slits. If the bright fringes on the screen are 20.0 cm apart, what color is the light?

Answer 1

Given,

$\\Distance\ between\ slits,\ d=1.50\mu m=1.50\times 10^{-6}m \\Distance\ from\ slits\ to\ screen,\ D=55cm=0.55m \\Fringe\ width,\ \beta =20cm=0.2m$

(Distance between two adjacent bright or dark fringes is called as fringe width)

In interference, the fringe width is given by,

je ie, 1=0.2 x 1.50 x 10-6 = 0.2 x = -=545.45 x 10-'m = 545.45nm 0.55

This wavelength of 545nm corresponds to GREEN (Emerald green to be precise)