What is the wavelength of the red light from a heliumneon la

What is the wavelength of the red light from a helium-neon laser when it is in glass with an index ofrefraction of 1.7? The wavelength in avacuum is 633 nm.
1 nm

What is thewavelength of the red light from a helium-neon laser when it is in glass with an index of refraction of1.7? The wavelength in a vacuum is 633 nm. (nm) = (_vac)/n = (633 nm)/(1.7) = 372 nm .