MCQ
In Young's double slit experiment, the slits are $0.5\, mm$ apart and interference pattern is observed on a screen placed at a distance of $1.0\, m$  from the plane containing the slits. If wavelength of the incident light is $6000 Å$, then the separation between the third bright fringe and the central maxima is......$mm$
  • A
    $4$
  • $3.5$
  • C
    $3$
  • D
    $2.5$

Answer

Correct option: B.
$3.5$
b
(b)Separation ${n^{th}}$bright fringe and central maxima is ${x_n} = \frac{{n\lambda D}}{d}$
So, ${x_3} = \frac{{3 \times 6000 \times {{10}^{ - 10}} \times 1}}{{0.5 \times {{10}^{ - 3}}}} = 3.5\,mm.$

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