Light of wavelength 597 nm falls on a double slit, and the first bright fringe of the interference pattern is seen at an angle of 15.8° with the horizontal. find the separation between the slits. µm

2.2 µm

Explanation:

For constructive interference, the expression is:

Where, m = 1, 2, .....

d is the distance between the slits.

Given wavelength = 597 nm

Angle,  = 15.8°

First bright fringe means , m = 1

So,

Also,

1 nm = 10⁻⁹ m

1 µm = 10⁻⁶ m

So,

1 nm = 10⁻³ nm

Thus,

Distance between slits ≅ 2.2 µm

The separation between the slit is

Solution:

As per the question:

Wavelength of light,

Now, by Young's double slit experiment:

here,

n = 1

x = slit width

Therefore,