Q. The distance between the first and the sixth minima in the diffraction pattern of a single alit is 0.5 mm. The screen is 0.5 m away from the slit. If the wavelength of light used is 5000 $\mathring{\mathrm{A}}$, then the slit width will be
A) 5 mm
B) 2.5 mm
C) 1.25 mm
D) 1.0 mm
Explanation
(b) Distance between first and sixth minima
$x = \frac{5\lambda D}{d}$
$\therefore\ \ a = \frac{n\lambda D}{x} = \frac{1 \times 500 \times 10^{- 10} \times 2}{0.5 \times 10^{- 3}}$
$d = 2.5 \times 10^{- 3}m = 2.5\ mm$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.