Question

A thin paper of thickness 0⋅02 mm having a refractive index 1⋅45 is pasted across one of the slits in a Young’s double slit experiment. The paper transmits 4/9 of the light energy falling on it. (a) Find the ratio of the maximum intensity to the minimum intensity in the fringe pattern. (b) How many fringes will cross through the centre if an identical paper piece is pasted on the other slit also? The wavelength of the light used is 600 nm.

Answer 1

Given:

The thickness of the thin paper =t=0.02 mm=0.02×10⁻³m

Refractive index of the paper=μ=1.45

Wavelength of the light,  λ=600 nm=600×10⁻⁹ m

(a) Let the intensity of the source without paper = I1

and intensity of source with paper =I2

Let a1 and a2 be corresponding amplitudes.

According to the question :

I2=[4/9] I1

We know that

I1 / I2=a₁²/a₂²      

∵ I ∝a²

⇒a1/a2=32

Here, a is the amplitude.

We know that  I max/ Imin =(a1+a2)²/ (a1-a2)².

⇒ Imax/ Imin=(3+2)²/ (3-2)²    

  =25/1

⇒Imax:Imin=25 : 1

(b)

Number of fringes that will cross through the centre is given by

n=(μ-1)t/λ.

⇒n=(1.45-1)×0.02×10⁻³/600×10⁻⁹

   =0.45×0.02×10⁴/ 6

=15

Answer 2

Explanation:

A thin paper of thickness 0⋅02 mm having a refractive index 1⋅45 is pasted across one of the slits in a Young’s double slit experiment. The paper transmits 4/9 of the light energy falling on it. (a) Find the ratio of the maximum intensity to the minimum intensity in the fringe pattern. (b) How many fringes will cross through the centre if an identical paper piece is pasted on the other slit also? The wavelength of the light used is 600 nm. ñ to I will follow you up then then then with then then then do then do with do with do with do with do with do do then do then do then do with do with do with do then with water do water do water water you water you sir you sir you sir you sir but request you for the Hindi don't English class work class work 7