Question

A radioactive nuclide samle has a half-life of 2 days . If 3 Kg of sample remains after 8 days , what was the initial mass of sample ?

A. 48Kg B.12Kg
C.15 Kg D.9kg

Answer 1

8 da / 2 da/half = 4 half lives in 8 days

N = 1/2^4 N0 = N0 / 16

1/16 of the sample remain

N0 = 16 * 3 kg = 48 kg

(A) is correct