A source contains two phosphorous radio nuclides ³²₁₅P (T_1/2 = 14.3d) and ³³₁₅P (T_1/2 = 25.3d). Initially, 10% of the decays come from ³³₁₅P. How long one must wait until 90% do so?

Question

A source contains two phosphorous radio nuclides 32 15 P (T 1/2 = 14.3d) and 33 15 P (T 1/2 = 25.3d). Initially, 10% of the decays come from 33 15 P. How long one must wait until 90% do so?

Philoid · Accepted Answer

Half-life of

Thus the source have initially 10% of .

Suppose after some time t, this situation may be reversed.

Let,

Initial number of nucleus of

For

∴ ……………(1)

For

∴ ……………(2)

On dividing equation (1) by equation (2) we get,

⇒

∴

Thus,

A source contains two phosphorous radio nuclides 3215P (T1/2 = 14.3d) and 3315P (T1/2 = 25.3d). Initially, 10% of the decays come from 3315P. How long one must wait until 90% do so?

A source contains two phosphorous radio nuclides ³²₁₅P (T_1/2 = 14.3d) and ³³₁₅P (T_1/2 = 25.3d). Initially, 10% of the decays come from ³³₁₅P. How long one must wait until 90% do so?