An accident occurs in a laboratory in which a large amount of a radioactive material, having a half
Channel: Doubtnut
Date: 16/08/2020

An accident occurs in a laboratory in which a large amount of a radioactive material, having a half life of `20` days, becomes embeded in the foor and walls so that the level of adiation is `32` times the permissible level. The laboratory can be safely occupied after