Question

Parallel light with a wavelength of 450 nm illuminates a single slit. The resulting image appears on a square screen, 1 mx 1 m, which is 1 m from the slit. The slit and the image on the screen are on the optic axis and the incoming light is parallel to the optic axis. What slit width will cause the first dark fringe to be at the edge of the screen ?

Answer 1

d = .9 x 10⁻⁶ m

Step-by-step explanation:

The central bright fringe flanked by bordering two dark fringe will cover the whole of square screen.

Width of central fringe =
`(2\lambda D)/(d)`

Where λ is wave length of light , D is distance of screen , d is slit width

putting the values we get

`(2* 450* 10^(-9))/(d)=1\\</p><p>d=0.9\mu m`