Question

activity of a freshly prepared radioactive sample is 10 to the power 10 disintegration per second whose mean life 10 to the power 9 second the mass of an atom of this radioisotope is 10^-25 kg. calculate the mass of the radioactive sample .​

Answer 1

ⓗⓛⓞ ⓜⓐⓣⓔ

activity of a radioactive sample is given by :-

-dN/dt= lemda N

N= 1/lemda (-dN/dt)

since,1/ lemda = t av.

N = t av. (-dN/dt)

= 10^9×10^10

= 10^19

mass of radioactive sample = mN

= 10^-25×10^19Kg

= 10^-6Kg

= 1mg

тℏᾰℵкṧ ❤

Answer 2

Heya user here u go

Activity of a radioactive sample is given by :-

-dN/dt= lemda N

N= 1/lemda (-dN/dt)

since,1/ lemda = t av

N = t av. (-dN/dt)

= 10^9×10^10

= 10^19

mass of radioactive sample = mN

= 10^-25×10^19 Kg

= 10^-6 Kg

= 1 mg

∴mass of the radioactive = 1 mg