Q. In a Young’s double slit experiment(slit distance d) monochromatic light of wavelength$\ \ \lambda\ \ $is used and the fringe pattern observed at a distance$\ \ L\ from\ the\ slits.\ $ The angular position of the bright fringes are
A) $\sin^{- 1}\left( \frac{n\lambda}{d} \right)$
B) $\sin^{- 1}\left( \frac{\left( n + \frac{1}{2} \right)\lambda}{d} \right)$
C) $\sin^{- 1}\left( \frac{n\lambda}{L} \right)$
D) $\sin^{- 1}\left( \frac{\left( n + \frac{1}{2} \right)\lambda}{L} \right)$
Explanation
(a) For constructive interference
Path difference $\mathrm{\Delta}\ = d\sin\theta = n\lambda$
$\Rightarrow \ \ \ \ \ \theta = \sin^{- 1}\left\lbrack \frac{n\lambda}{d} \right\rbrack$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.