Ultraviolet germicidal lamps are installed in hospital air-handling systems to reduce airborne pathogens. Which property of ultraviolet radiation makes it better suited for this purpose than visible or infrared light?
(a) Ultraviolet radiation travels more slowly in air than visible light, increasing the exposure time of microbes.
(b) The lower photon energy of ultraviolet light allows it to penetrate cells without damaging them.
(c) Higher photon energy of ultraviolet light can break molecular bonds in microorganisms' DNA.
(d) The very short wavelength of ultraviolet light lets it penetrate more deeply into microbes, enhancing disinfection.