What is the minimum thickness of a coating of magnesium fluoride (n = 1.38) applied to glass (n = 1.50) that gives a minimum reflection for 600 nm light?
A) 600 nm
B) 300 nm
C) 435 nm
D) 109 nm
E) 100 nm

Question

Quizplus · Accepted Answer

The minimum reflection occurs when the thickness of the coating corresponds to a quarter-wavelength of the incident light.

Using the formula:

t = (λ/4) * (n2 - n1)

where t is the thickness of the coating, λ is the wavelength of the incident light (600 nm), n1 is the refractive index of glass (1.50), and n2 is the refractive index of magnesium fluoride (1.38).

Plugging in the values, we get:

t = (600/4) * (1.38 - 1.50)

t = 109 nm

Therefore, the minimum thickness of the coating should be 109 nm to produce a minimum reflection for 600 nm light.

What Is the Minimum Thickness of a Coating of Magnesium