Two thin layers of material with different indices of refraction are coated on a glass plate.The outer first material has n₁ = 1.404,the inner second material has n₂ = 1.531,and the glass has n_glass = 1.62.If light is incident from air on the first layer,what is the phase change for light that reflects from the glass? A)0 $\degree$ B)180 $\degree$ C)360 $\degree$ D)540 $\degree$

Question

Quizplus · Accepted Answer

When light reflects from a medium with a higher refractive index to a medium with a lower refractive index, there is a phase change of 180 degrees. Since light is incident from air (which has a lower refractive index than glass) onto the first layer (which has a higher refractive index than air), there will be no phase change at this interface. However, when the light reaches the glass (which has a higher refractive index than the second layer), there will be a phase change of 180 degrees upon reflection. Therefore, the total phase change for light that reflects from the glass is 180 degrees. Choice B is the correct answer.

Two Thin Layers of Material with Different Indices of Refraction °\degree°

Two Thin Layers of Material with Different Indices of Refraction $\degree$