Question

Monochromatic light falling on two slits 1.5x10^-2 mm apart produces the fifth-order fringe at an 8.9° angle. What is the wavelength of the light used? Express your answer using two significant figures.

Answer 1

Wavelength will be
`0.464\mu m`

Explanation:

We have given distance between the two slits
`d=1.5* 10^(-2)mm=1.5* 10^(-5)m`

Angle
`\Theta =8.9^(\circ)`

We know that for nth order fringe
`dsin\Theta =n\lambda`

In question it is given that 5th order so n =5

So
`1.5* 10^(-5)sin\8.9 =5\lambda`

`\lambda =.464* 10^(-6)m=0.464\mu m`

So wavelength will be
`0.464\mu m`