Which among alpha, beta and gamma emitters is most dangerous for human body? Lets say we have three candies: One with alpha emitter in it, one with beta emitter in it and one with gamma emitter in it. All have similar activities. You must eat one, put one in your pocket and throw the last one out of the window. Which candies should you choose for each task?
I am a bit confused. I read a little bit of literature about alpha, beta and gamma rays and I'm not sure how to choose the suitable ones for the given tasks. Please explain the reasons.
 A: I would eat the gamma emitter, since gamma rays have a very small chance to be stopped by the human body to begin with. The difference between a gamma source inside your body, and a gamma source outside, is negligible.
I would pocket the alpha emitter. While alpha particles are big and heavy, essentially Helium nuclei (two protons and two neutrons), and are thus very high energy, they don't tend to travel very far, and have trouble penetrating even the outermost layers of skin. Alpha particles are extremely dangerous inside the body, so eating or inhaling it would be a very bad idea.
I would throw the beta emitter out the window. Beta particles are single electrons. While they can be stopped by clothing most of the time, and something like aluminum foil almost all the time. That said, if they do penetrate deeper, they could still potentially cause problems including radiation burns to deeper portions of skin. They're fairly unlikely to cause cancer... but I'd still toss it.
Also, for a slightly more tongue-in-cheek reason to pocket the Alpha emitter instead of the other two... if you throw it out the window and a child or animal eats it, they're in serious trouble. At least pocketing it, you're minimizing the danger to others.
FYI, a neutron emitter would be by far the most dangerous... unfortunately merely throwing one out the window wouldn't help all that much. That one, I'd hand over to the appropriate authorities, or perhaps bury as deep underground as I could.
A: Among the three candies gamma has the least destructive power but have high penetrative power where alpha is just the vice versa of gamma having high destructive power and least penetrative power.
So if you consume the gamma candy you should be least damaged from inside among the three, you can keep the alpha particle in the pocket as if it's outside human body it is least likely to penetrate inside, while beta should be thrown as it can penetrate(not as high as gamma) and it has destructive power too(not as high as alpha).
But the fact is you are most likely to die whichever you consume depending upon the amount.
