Question

In young's double slit experiment `"d"/"D"`= 10^-4 D (d = distance between slits, D = distance of screen from the slits). At a point P on the screen resulting intensity is equal to the intensity due to individual slit l₀. Then the distance of point P from the central maximum is (λ = 6000 `"A"^°`)

Options

• 2 mm

• 1 mm

• 0.5 mm

• 4 mm

Answer 1

2 mm

Explanation:

l = 4 l₀ cos²`(phi/2)`

l₀ = 4 l₀ cos²`(phi/2)`

∴ cos `(phi/2) = 1/2`

or = `phi/2 = pi/3`

or `phi = (2pi)/3=((2pi)/lambda).Deltax`

or `1/3=(1/lambda)"y"."d"/"D"(Deltax="yd"/"D")`

∴ `y =lambda/(3xxd/D)= (6xx10^-7)/(3xx10^-4)=2xx10^-3`

m = 2 mm