It would be the same thing if the Co does not have a number with it because it can’t reduce
Answer:
To the best of my knowledge, it is because of the amount of gamma rays is given off.
Explanation:
While both are isotopes, Potassium 40 gives off fewer gamma rays compared to Cobalt 60. Potassium 40 isn't really harmful to humans, but Cobalt 60 (I believe) is used in chemotherapy.
Base on the question all about the human eye were an optic nerve of it needs an energy of 2.10x10^-17J that could trigger a series of impulses that eventually reach to the brain. So the possible photons of blue light needed for for this energy is 52 photons