The activity of a freshly prepared radioactive sample is disintegrations per second, whose mean life is . The mass of an atom of this radioisotope is . The mass (in mg) of the radioactive sample is
Answer: 1
Solution
Activity , where (τ is mean life).
Mass of sample:
Mass of sample:
JEE Advanced · 2011 · 10 Apr 2011 · Paper 1 · Integer answer