Question

Coherent light from a laser shines through two slits 0.002 cm apart, producing an interference pattern on a screen. A bright central fringe is seen on the screen in line with a point directly between the slits. The next bright fringe is seen at an angle of 2 degrees above the central fringe (with a dark fringe between). What is the wavelength of the laser’s light? (1 nm = 10-9 m)

Answer 1

λ = 698 nm (Approx)

Step-by-step explanation:

Given:

Width d = 0.002 cm = 0.002 x 10⁻² nm

θ = 2°

Computation:

d sinθ = mλ

(0.002 x 10⁻²) sin2° = mλ

λ = 698 nm (Approx)