Question

1. In YDSE a transparent sheet of refractive mex
(u = 1.5) and thickness 1.5 um is introduced in
the path of one of the waves, then intensity at
position of central maxima is (I intensity in
absence of sheet, = 5000 A)
(1)I/2
(2)I
(3)2I
(4)Zero​

Answer 1

answer : option (2) I

it is given that In YDSE a transparent sheet of refractive index (n = 1.5) and thickness, t = 1.5 μm is introduced in the path of one of the waves,

wavelength of monochromatic wave, λ = 5000 Å

= 5000 × 10^-10 m = 5 × 10^-7 m

first find phase difference, Φ = 2π/λ (u - 1)t

= 2π/(5 × 10^-7) × (1.5 - 1) × 1.5 × 10^-6

= 2π/(5 × 10^-7) × 0.75 × 10^-6

= 15π/5

= 3π

now using formula, I₁ = Icos²Φ

=Icos²(3π)

= I × (-1)²

= I

hence intensity at Central maxima remains unchanged. i.e., I

Answer 2

Answer:

answer : option (2) I

it is given that In YDSE a transparent sheet of refractive index (n = 1.5) and thickness, t = 1.5 μm is introduced in the path of one of the waves,

wavelength of monochromatic wave, λ = 5000 Å

= 5000 × 10^-10 m = 5 × 10^-7 m

first find phase difference, Φ = 2π/λ (u - 1)t

= 2π/(5 × 10^-7) × (1.5 - 1) × 1.5 × 10^-6

= 2π/(5 × 10^-7) × 0.75 × 10^-6

= 15π/5

= 3π

now using formula, I₁ = Icos²Φ

=Icos²(3π)

= I × (-1)²

= I

hence intensity at Central maxima remains unchanged. i.e., I