Question

You shine a monochromatic light at glass (n=1.5), what percent of the light will reflect (n-air=1.0)?

A) 4%
B) 8%
C) 12%
D) 16%

Answer 1

Using the Fresnel equations for normal incidence, the percentage of monochromatic light that reflects when it hits glass with an index of refraction of 1.5 is calculated to be 4%.

Step-by-step explanation:

The question involves calculating the percentage of monochromatic light that will reflect when it hits a glass surface with a given index of refraction. The relevant formula to find the reflectance at normal incidence (the Fresnel equations for normal incidence) can be given by:

R = ((n1 - n2) / (n1 + n2))^2

Where:

• R is the reflectance (the fraction of power reflected)
• n1 is the index of refraction of the first medium (air, in this case)
• n2 is the index of refraction of the second medium (glass, in this case)

In this instance, the indices of refraction are:

• n1 = 1.0 (air)
• n2 = 1.5 (glass)

Plugging these values into the equation:

R = ((1.0 - 1.5) / (1.0 + 1.5))^2 = (-0.5 / 2.5)^2 = 0.04

Therefore, the percentage of light that reflects off the glass at normal incidence is 4%, which corresponds to answer choice A).