Question

A monochromatic beam of light falls on YDSE apparatus at some angle(say theta) as shown in figure.
A thin sheet of glass is inserted in front of the lower slit S2. The central bright fringe(path difference 0) will be obthained

a) at O
b)above O
c)below O
d) anywhere depending on angle theta , thickness of plate t and refractive index of glass "mu"

Answer 1

Would you like to make an attempt ??

Answer 2

Can you solve the problem if the glass sheet is in front of upper slit S1 instead?

Answer 3

I know that placing a glass slab will shift the position of the central bright and by how much.
I don't know what the inclination of the incident beam has to do with anything

Answer 4

Do you know - what is a wavefront ??

Answer 5

a set of particles vibrating in phase?? u mean the definition?

Answer 6

you see i've only done mostly very simple problems on wave optics

Answer 7

Think in terms of time it takes light to reach the screen.
The central fringe means travel times are equal on both sides of the interferometer from source to point on the screen.

Answer 8

yes the path diff is 0
i want to know the significance of the beam's inclination

Answer 9

?

Answer 10

r u there?

Answer 11

The inclination means that light reaches S2 before it reaches S1, hence an induced time lag before the slits.
It means that, without any glass sheet, the central fringe would be above point O because of this inclination.