Question

Light of wavelength 550 nm comes into a thin slit and produces a diffraction pattern on a board 8.0 m away. The first minimum dark fringe appears 3 mm from the central maximum. What is the width of the slit?

Answer 1

Width of the slit will be equal to 1.47 mm

Step-by-step explanation:

We have given wavelength of the light
`\lambda =550nm=550* 10^(-9)m`

Distance D = 8 m

Distance between first minimum dark fringe and the central maximum is 2 mm

So
`x=3* 10^(-3)m`

We have to find the width of the slit

For the first order wavelength is equal to
`\lambda =(x)/(D)* a`, here a width of slit

So
`a=(\lambda D)/(x)=(550* 10^(-9)* 8)/(3* 10^(-3))=1466.666* 10^(-6)=1.47mm`

So width of the slit will be equal to 1.47 mm