Final answer:
Cathode rays would still be generated without the fluorescent screen, but would not be visible. X-rays might be produced in old CRT televisions but are typically shielded. The claimed reverse process of converting visible light to ultraviolet light by fluorescent materials is untypical and requires verification.
Step-by-step explanation:
If the fluorescent screen were removed from a cathode ray tube (CRT), cathode rays, which are essentially a stream of electrons, would still be generated because their production is not dependent on the presence of the screen. However, without the fluorescent screen, you would not be able to see the cathode rays because the visible light is produced when the electrons interact with the phosphors on the screen. The cathode rays themselves do not produce light that is visible to the human eye.
Regarding CRTs in older television tubes using a 30-kV accelerating potential, x-rays could be generated when electrons strike materials at high velocities. Nevertheless, televisions are designed with shielding to protect users from potential x-ray emission.
The emission of visible light from fluorescent materials occurs when they absorb ultraviolet light and re-emit it as visible light. While the reverse process seems theoretically plausible, it would involve converting lower energy visible light into higher energy ultraviolet light, which is not typically how fluorescent materials operate. Therefore, the inventor's claim requires significant scrutiny and verification.
Lastly, fluorescence and phosphorescence are both forms of luminescence, but they differ in duration. Fluorescence stops almost immediately when the light source is removed, whereas phosphorescence can continue to emit light for a period of time after the excitation source is removed.