Final answer:
The life of an x-ray tube is measured based on usage factors, and x-rays can be generated in devices like CRT TVs where electrons are accelerated by a potential and collide with the screen, emitting photons.
Step-by-step explanation:
The life of an x-ray tube is measured based on a few factors, including the total number of exposures, the duration of use, the intensity of the electron beam, and the type of anode material used. X-rays are generated when accelerated electrons strike a metallic target, releasing energy in the form of x-ray photons. This can happen, for example, within a color television tube where electrons are accelerated using a high voltage power source and strike the screen, potentially generating x-rays.
Regarding a color television tube generating x-rays, the shortest wavelength of such x-rays can be calculated using the energy of the electrons that are accelerated by a potential. When a 30.0-kV potential accelerates electrons towards the screen, this potential difference can be converted into kinetic energy and subsequently into the energy of the photon, which, after applying Planck's relation, will give the shortest wavelength of the x-rays produced.