Question

(i) In Young’s double slit experiment, derive the condition for (a) constructive interference and (b) destructive interference at a point on the screen.
(ii) A beam of light consisting of two wavelengths, 800 nm and 600 nm is used to obtain the interference fringes on a screen placed 1.4 m away in a Young’s double slit experiment. If the two slits are separated by 0.28 mm, calculate the least distance from the central bright maximum where the bright fringes of the two wavelengths coincide.

Answer 1

Sorry but question is too long .

It is not eligible for understanding.

So can't understand.


PLEASE TRY SHORT NEXT TIME

Answer 2

Let a be the width of each slit. Linear separation between 10 bright fringes.

x = 10β =

d

10λD

corresponding angular separation

Θ

1

= x/D = 10λ/d

Now, the angular width of central maximum in the diffraction pattern of a single slit,

Θ

2

=2λ/a

As Θ

2

=Θ

1

2λ/a=10λ/d

or a = d/5 = 1.00/5 mm = 0.2mm