UVA light has a longer wavelength than UVC light. As a result, UVA light is less effective at killing bacteria and other microorganisms. When exposing bacteria to UVA light, the results may differ from those obtained with UVC light in that fewer bacteria will be killed or inactivated. UVC light has a shorter wavelength and is more effective at killing bacteria and other microorganisms. When exposing bacteria to UVC light, more bacteria will be killed or inactivated compared to UVA light.