Physics help (Radioactivity)

[Bugz]

These two questions are something I'm having real trouble with:

2. A person lives in a house, where the activity of the radon is the same as the gaseous beta emitter to which he is exposed at work. He spends similar lengths of time at home and at work. Which of the two sources poses the greatest risk to his health and why?

5. In the nuclear industry, storing a radioactive substance for a time of twenty half-lives is considered long enough for its safe handling. Explain why.

My answers were:

2. The gaseous beta emitter would be more dangerous to the person in question because radon will generally not be in an air-tight condition at home. This means it isn’t that harmful and is easily circulated using open windows and fans. However, a gaseous beta emitter features the use of beta particles which is more dangerous because it can past through light elements. This will be a problem since it can be inhaled and if it is a beta emitter, the concentration of radon will be in one place, since a beta emitter specifically emits beta particles.

5. By twenty half life’s, the nuclei which are unstable should have disintegrated. This will mean it will not emit as much radiant energy, which is dangerous to humans in the form of alpha or beta. Even if some unstable nuclei remain, they won’t pose as much as a threat as if there was the full, original amount.

Are these answers right?

Can someone answer the two questions for me so I can see where/if I fucked up.

Rep avalible <holds up shiny rep>

 

[fl3a]

sure they are correct, rep plz

 

[tris-]

might want to add why beta is bad. from what i remember, its because they travel slowly and are quite large so it physically damages the skin. or it could be because they travel quickly and are quite small.

some combination of big and small, fast and slow, is why they cause so much damage if they get inside the body

tis about 5 yrs since i did anything on radiation.

 

[swords]

2. Radon releases alpha particles when it decays so the question is actually asking, which is more dangerous to humans, alpha radiation or beta radiation. You are on the right lines with the answer but it feels like you waffled a bit. Try to focus the answer simply on the differences between alpha and beta radiation in the context of their hazardous properties.

5. well after 20 half lives there will be roughly 0.0001% of the original radioactivity. Seems like a significant reduction to me

 

[Bugz]

2. Radon releases alpha particles when it decays so the question is actually asking, which is more dangerous to humans, alpha radiation or beta radiation. You are on the right lines with the answer but it feels like you waffled a bit. Try to focus the answer simply on the differences between alpha and beta radiation in the context of their hazardous properties.

Ahhh

Thxs alot

 

[leviathane]

2. Radon releases alpha particles when it decays so the question is actually asking, which is more dangerous to humans, alpha radiation or beta radiation. You are on the right lines with the answer but it feels like you waffled a bit. Try to focus the answer simply on the differences between alpha and beta radiation in the context of their hazardous properties.

5. well after 20 half lives there will be roughly 0.0001% of the original radioactivity. Seems like a significant reduction to me

pretty much hit the nail on the head tbh

 

[swords]

I seem to have a knack for being able to answer science questions.

 

[Cadelin]

2. Radon releases alpha particles when it decays so the question is actually asking, which is more dangerous to humans, alpha radiation or beta radiation. You are on the right lines with the answer but it feels like you waffled a bit. Try to focus the answer simply on the differences between alpha and beta radiation in the context of their hazardous properties.

5. well after 20 half lives there will be roughly 0.0001% of the original radioactivity. Seems like a significant reduction to me

Just to add to swords posts.

2. They haven't given you enough information to make any judgement on the difference between work and home. What you know is that Radon produces alpha particles and the other source produces particles that emit beta particles. Both sources are gaseous. As they are gaseous you can breath them in and so even particles that travel only a very short distance will be absorbed. I would thus say that alpha particle source is more dangerous

5. After 20 half lives there will be (1/2)^20 of the original radioactivity as 2^10 is 1024 ~ 1000 that means it will be roughly 0.000001% !

 

[leviathane]

ye s'pose as alpha does more harm if inside the body than beta particles.

 

[swords]

If he's being exposed to the beta source at work has he been given adequate protective gear

for the 20 half lives i just took 100/2 twenty times came up with 0.0000953 so... dunno

 

[Darzil]

Externally, alpha particles are pretty harmless, they are essentially helium nuclei, and can't penetrate our skin to a dangerous depth. Beta particles, electons, can penetrate the skin, but have less energy. Externally, therefore, Beta is more harmful (more chance of causing damage) than Alpha.

Internally, we have less defence, so alpha can do damage, and as it has more energy than Beta, it is more dangerous.

As both sources are gaseous, and are breathed in, we have to consider the internal damage, so the alpha is worse than beta.

The half life thing is just the time until half the atoms have decayed. It's effectively never going to stop emitting, it'll just reach background levels eventually. My guess is that for most materials, by the time they reach 1 millionth of their original emission level (which is about what 20 half lives is), they will be pretty close to background levels. I'd have to know their original levels to be sure, though. You can find out such things I guess.

Leastways, that's what my answers would be, but it's a half a lifetime since I studied Physics A level.

Darzil

 

[Bugz]

Leastways, that's what my answers would be, but it's a half a lifetime since I studied Physics A level.

Is this A-Level then?

Teacher is telling us it's GCSE like its suppose to be easy :/

Hard stuff IMO.

 

[SethNaket]

Alpha particles are much more harmful than beta at the same activity, IF it gets inside your body first. What matters when radiation damages tissue is how much energy it deposits in the organ/cell/dna/whatever. Beta particles penetrate about 600 times deeper in air than alpha radiation, which means that for any given volume it only deposits 1/600th the energy of what an alpha particle would. Think of it like this, which will cause greater damage, punching one guy 600 times or punching 600 guys 1 time?

If the alpha source is outside your body however, it's harmless. So the answer to the question depends on wether any of the gases can get inside your body (into your lungs most likely).

 

[Naetha]

Also make a point about the radon gas building up in enclosed spaces which you will get in homes (i.e. cellars, downstairs toilets) but less so in work places where there is more air circulation, movement etc.

 

[swords]

And if he's working in an environment like that he should have adequate safety equiptment by law...