Question

Two narrow slits 84 mum apart are illuminated with light of wavelength 650 nm. What is the angle of the m = 3 bright fringe in radians What is the angle in degrees

Answer 1

Answer:

The angle is 1.33°.

Explanation:

Given that,

Distance $d=84\times10^{-6}\ m$

Wavelength = 650 nm

Number of fringe = 3

We need to calculate the angle

Using formula of angle for brightness

$d\sin\theta=m\lambda$

$\theta=\sin^{-1}\dfrac{m\lambda}{d}$

Where, d = distance

$\lambda$ =wavelength

m = number of fringe

Put the value into the formula

$\theta=\sin^{-1}\dfrac{3\times650\times10^{-9}}{84\times10^{-6}}$

$\theta=1.33^{\circ}$

Hence, The angle is 1.33°.