WAVES-DIRECTION-INTERFERENCE

Question

If some light passes through two slits, separated by 0.33 mm, and the first dark fringe is located 0.035° from the central antinode, the wavelength of the light is ___x10^-7m.

Answer 1

Distance between two slits d is 0.33 mm = 0.33 * 10^-3 m

First dark fringe means m = 0.5

Angle of Diffraction θ is 0.035°

We know that Double slit interference Equation m λ = d sin θ

λ = d sin θ / m

λ = (0.33 * 10^-3 * sin(0.035) ) / (0.5)

λ = 4.0317 * 10^-7 m.

Therefore the wavelength of the light is 4.0317 * 10^-7 m.