Question

Obtain the amount of necessary to provide a radioactive source of 8.0 mCi strength. The half-life of is 5.3 years.

Answer 1

The strength of the radioactive source is given as:

Where,

N = Required number of atoms

Half-life of, = 5.3 years

= 5.3 × 365 × 24 × 60 × 60

= 1.67 × 10⁸ s

For decay constant λ, we have the rate of decay as:

Where, λ

For:

Mass of 6.023 × 10²³ (Avogadro’s number) atoms = 60 g

∴Mass of atoms

Hence, the amount of necessary for the purpose is 7.106 × 10⁻⁶ g.