Question

A screen is placed 60.0 cm from a single slit, which is illuminated with light of wavelength 690 nm. If the distance between the first and third minima in the diffraction pattern is 3.10 mm, what is the width of the slit?

Answer 1

slit width, b = 0.2671 mm

Given:

distance of screen from the slit, x = 60.0 cm

wavelength of light,
`\lambda = 690 nm = 690* 10^(- 9) m`

distance between 1st and 3rd minima, t = 3.10 mm =
`3.10* 10^(-3) m`

Solution:

Calculation of the distance between 1st and 3rd minima:

`t = ((3 - 1)\lambda x)/(b)`

`3.10* 10^(- 3) = (2* 690* 10^(-9)* 60.0* 10^(-2))/(b)`

b = 0.2671 mm

slit width, b = 0.2671 mm