Nucleus X decays radioactively to nucleus Y

PHYSICS · Single correct · A Level · Physics · Nuclear physics · Nuclear physics

Problem

Nucleus X decays radioactively to nucleus Y, which is itself radioactive. The half-life of X is

8\,\text{h}

, and the half-life of Y is

2\,\text{h}

. A sample initially contains only nuclei X. After

8\,\text{h}

, what is the ratio

N_Y/N_X

of the number of Y nuclei to the number of remaining X nuclei? (a)

0.44

(b)

1.0

(c)

0.29

(d)

0.18