Monochromatic (single-wavelength) light falling on two slits 0.016 mm apart produces the fifth-order bright spot at an 8.8◦angle. What is the wavelength of the light used?

Given Information:  

distance = d = 0.016 mm = 0.0016 cm = 0.000016 m

Angle = θ = 8.8°

bright spot = m = 5

Required Information:  

Wavelength =  λ = ?

Wavelength = 4.89x10⁻⁷ m

Explanation:

Monochromatic light passes through a double slit. The corresponding diffraction is given by the equation:

dsinθ = mλ

where d is the distance between two slits, m is the order of the diffraction, θ is the angle and λ is the wavelength of the light wave.

λ = dsinθ/m

λ = 0.016*sin(8.8°)/5

λ = 4.89x10⁻⁷ m

Therefore, the wavelength of the monochromatic light falling on two slits is 4.89x10⁻⁷ m