Q. In a Young’s double slit experiment (slit distance $d$) monochromatic light of wavelength $\lambda$ is used and the figure 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) [image:10_image30.png]
The condition for bright fringes is,
Path difference, $\delta = d\sin{\theta_{bright} = N\lambda}$
Where, $N = 0, \pm 1, \pm 2$
The angular position of the bright fringes is $\theta_{bright} = \sin^{- 1}\left( \frac{N\lambda}{d} \right)$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.