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

`d=1.29*10^(-6)m`

Step-by-step 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=(n*\lambda*D)/(y)`

`d=(2*431 *10^(-9)m*1.4)/(0.803)`

`d=1.29*10^(-6)m`