【单选题】Ultraviolet light of wavelength 350 nm and intensity 1.00 W/m 2 is directed at a potassium surface. The maximum kinetic energy of the photoelectrons is ( )
【单选题】Consider: radio waves (r), visible light (v), infrared light (i), x-rays (x), and ultraviolet light (u). In order of increasing frequency, they are:
【单选题】The gas present in the stratosphere which filters out some of the sun's ultraviolet light and provides an effective shield against radiation damage to living things is