Hello! I'm not really into physics that much, and in school I didn't study it that much either, so this question will probaby look silly to you. I have a question about radioactivity: When an object/human being is exposed to radiation, does it continue to emit rays? Because in most documentaries or movies I watch, people who have been exposed to radiation, let's say, just hours before, can be measured with detectors and the level of their exposure can even be calculated, or at least that's what they say. Like I remember from documentaries or even movies, people who get exposed are forced to take showers to get some of the radioactive material from them, but it is also said that just the shower won't get it all off. My question is this, is it true that a human exposed to this material (for example, let's say a liquidator on top of the roof of Chernobyl, back in 1986) is also going to emit radiation after being exposed to it? Now this baffles me, because from what I remember from those classes, only those radioactive atoms can emit rays. Don't they have to get on top of him/inside him to still emit from his body? If so, how? The only possible explanation I see is air. But what if the object is solid and is radioactive? Are there still atoms floating in the air, which escaped the solid mass? Is that even possible? Maybe some particles coming from smoke could get on top of the clothes, but the only way to get into the body is through the mouth or nose. But if he's covering it with the gasmask, sure gas mask won't help with the rays, but shouldn't it at least protect him from the particles themselves? It's probably a stupid question, but keep in mind that I will only get smarter if you explain everything thoroughly. And yes, I did google about radiation, read articles but didn't see anything that would help me out on this. Thanks in advance!