To ensure almost 100% transmissivity, photographic lenses are often coated with a thin layer of dielectric material. The refractive index of this material is intermediated between that of air and glass (which makes the optical element of the lens). A typically used dielectric film is (n = 1.38). What should the thickness of the film be so that at the centre of the visible spectrum (5500 ), there is a maximum transmission.
© 2026 GoodEd Technologies Pvt. Ltd.
