Interference fringes are observed on a screen by illuminating two thin slits 1mm apart with a light source (λ = 632 . 8nm) . The distance between the screen and the slits is 100cm . If a bright fringe is observed on a

Correct answer: A. 1 . 27 = dsinθ = dθ = (dy)/(D) = 10 ^ - 3 × 1 . 270mm 1m = 1 . 27 1 . 27

JEE Main 20202 SeptemberMorning Shift

JEE Main 2020 · 2 September · Morning Shift · Physics · Wave Optics

Interference fringes are observed on a screen by illuminating two...

Interference fringes are observed on a screen by illuminating two thin slits

1mm

apart with a light source \left(\lambda = 632 . 8nm\right)

. The distance between the screen and the slits is

100cm

. If a bright fringe is observed on a screen at distance of

1 . 27mm from the central bright fringe, then the path difference between the waves, which are reaching this point from the slits is close to :

A. $1 . 27\mum$

$\DeltaP = dsin\theta$

$= d\theta$

$= \dfrac{dy}{D} = \dfrac{{10}^{- 3} \times 1 . 270mm}{1m} = 1 . 27\mum$

$1 . 27\mum$