Question

if you don't know don't give the answer

with explanation ​

Answer 1

ⓗⓔⓨⓐ

shift upward by nearly 2 fringes ✌✌✌

Answer 2

⊕ANSWER⊕

When a thin film is placed in the path of one of the beams, then the optical path of that beam gets longer.

The path difference is  

Δx=(μ−1)t  

where μ is refractive index, t is thickness.  

Given μ=1.5,t=2×10−6 m  

∴Δx=(1.5−1)×2×10−6=10−6 m=1 μm  

Also path difference Δx=dyD  

⇒y=DdΔx  

Also fringe width is given by  

β=Dλd  

=Dd×500×10−9=Dd×0.5 μm  

y=Dd×1 μm  

=2×Dd×12μm=2β  

Hence, central maxima shifts upward by nearly two fringes.