Question

Two straight narrow parallel slits $3 mm$ apart are illuminated with monochromatic light of wavelength $5900 \times 10^{-8} cm .$ Fringes are observed at a distance of $3 cm$ from the slits. Find the width of fringes.

• A. $0.51 mm$
• B. $0.52 mm$
• C. $5.9 \mu m$
• D. $0.59 m$

Answer 1

Answer: (C)

we know, $\beta=\frac{\lambda D }{ d }$
$=\frac{5900 \times 10^{-10} \times 3 \times 10^{-2}}{3 \times 10^{-3}}$
$\beta=5.9 \times 10^{-6} m$
$\beta=5.9\, \mu m$