An electromagnetic wave has wavelength 600 nm in vacuum. It enters a transparent medium of refractive index 1.5. If its wavelength in the medium is N nm, find N.

Question

G1 Physics · Accepted Answer

Frequency remains unchanged on entering the medium. Wave speed becomes v = c/n. Therefore wavelength becomes λₘ = λ₀/n. Thus, λₘ = 600/1.5 = 400 nm. Hence N = 400.