Question

Monochromatic light falls on two narrow slits that are 0.05 mm apart. The second order bright fringe appears 12 cm from the center maximum on a screen 5 meters away. What is the wavelength of the incident light?

Answer 1

Answer:

λ = 1.2 x 10⁻⁶ m

Explanation:

Given that,

slit separation,  d = 0.050 mm

                            = 5 x 10⁻⁵ m

Distance between the fringes, D = 5.00 m

distance between the fringes, x = 12.0 cm

                                                    = 0.12 m

wavelength of the light = ?

the separation between the fringe is given by

$x = \dfrac{n\lambda\ D}{d}\\\\\lambda = \dfrac{x d}{n\ D}$

where as n = 1

$\lambda = \dfrac{0.05\times 10^-^3\times 0.12}{1\times 5.00}$

λ = 1.2 x 10⁻⁶ m