Question

An instructor wishes to determine the wavelength of the light in a laser beam. To do so, she directs the beam toward a partition with two tiny slits separated by 0.195 mm. An interference pattern appears on a screen that lies 4.85 m from the slit pair. The instructor's measurements show that two adjacent bright interference fringes lie 1.55 cm apart on the screen. What is the laser's wavelength (in nm)

Answer 1

Answer:

λ = 623.2 nm

Explanation:

We are given;

separation distance; d = 0.195 mm = 0.195 × 10^(-3) m

interference pattern distance; D = 4.85 m

Width of two adjacent bright interference; w = 1.55 cm = 1.55 × 10^(-2) m

Formula for fringe width is given as;

w = λD/d

Where λ is wavelength

Thus;

λ = dw/D

λ = (0.195 × 10^(-3) × 1.55 × 10^(-2))/4.85

λ = 0.0000006232 m

Converting to nm gives;

λ = 623.2 nm