Question

A strontium vapor laser beam is reflected from the surface of a CD onto a wall. The brightest spot is the reflected beam at an angle equal to the angle of incidence. However, fringes are also observed. If the wall is 1.2 m from the CD, and the second bright fringe is 0.803 m from the central maximum, what is the spacing (in m) of grooves on the CD

Answer 1

Answer:

$d=1.29*10^{-6}m$

Explanation:

From the question we are told that:

Distance of wall from CD $D=1.4$

Second bright fringe $y_2= 0.803 m$

Let

Strontium vapor laser has a wavelength \lambda= 431 nm=>431 *10^{-9}m

Generally the equation for Interference is mathematically given by

$y=frac{n*\lambda*D}{d}$

Where

$d=\frac{n*\lambda*D}{y}$

$d=\frac{2*431 *10^{-9}m*1.4}{0.803}$

$d=1.29*10^{-6}m$