If the wavelength of light in vacuum is 469 nm, what is the wavelength of light in a thin film of index of refraction 1.42?
A) 110 nm
B) 220 nm
C) 330 nm
D) 440 nm
E) 550 nm

Question

Quizplus · Accepted Answer

When light travels from a medium with one index of refraction (in this case, vacuum) into a medium with a different index of refraction (in this case, the thin film), the wavelength of the light changes according to the formula:

λ = λ0/n

where λ is the new wavelength, λ0 is the original wavelength in vacuum, and n is the index of refraction of the medium the light is traveling through. Plugging in values, we get:

λ = 469 nm / 1.42 = 330 nm

Therefore, the answer is C).

If the Wavelength of Light in Vacuum Is 469 Nm