After the x-ray unit is turned off, do x-rays continue to exist in the room?

• A. Yes
• B. No
• C. Only if there is a capacitor in the tube
• D. Only if a phosphor plate stores energy

Answer: (B)

X-rays are produced only while the tube is energized. Once you turn the unit off, there’s no source pushing electrons to generate new x-ray photons, so no ongoing x-ray beam exists. Any photons already in the room would be quickly absorbed by walls, the floor, and equipment, so there’s no persistent radiation. A phosphor plate stores the latent image by chemical or electronic means, not as continuing x-ray energy, so it does not emit x-rays after exposure ends. While there may be some scatter during exposure, it dissipates when the exposure stops.