# Nuclear Physics

1. May 23, 2006

### petuniac

QUESTION

in an accident in a lab a radioactive isotope with a half life of 3 days is spilled - as a result the radiation is 8 times the max. permissible amount, how long must workers wait before they can enter the room.

9

2. May 23, 2006

### Pengwuino

Do you know what half life means?

3. May 23, 2006

### petuniac

half life is the amount of time it takes for the quantity to reduce to half it's initial value.. in this question it takes 3 days for us to get half of the material

4. May 23, 2006

### Pengwuino

So this should be fairly straight forward. If you have 8x the amount and it takes 3 days for half to decay away, how long should it take

5. May 23, 2006

### petuniac

huh?

maybe i am missing something here.. but that wouldn't give me 9 as a solution... sorry, I appreciate your help, but am lost on this one.... please help

6. May 24, 2006

### daveb

If the radiation is 8x the maximum, 3 days later (which is 1 half life) the radiation would be 4x maximum. Can ou go from there?

7. May 25, 2006

### petuniac

Thanks. Got it now!