Question

The rate of radioactive disintegration at an instant for a radioactive sample of half-life 2.2 x 10⁹ s is 10¹⁰ s^-1. The number of radioactive atoms in that sample at that instant is, ______ 

विकल्प

• 3.17 x 10¹⁹

• 3.17 x 10²⁰

• 3.17 x 10¹⁷

• 3.17 x 10¹⁸ 

Answer 1

3.17 x 10¹⁹

Explanation:

Given:

T_1/2 = 2.2 x 10⁹ s and rate of disintegration,

R = λN = `0.693/"T"`N ..............`(∵ lambda = 0.693/"T")`

∴ `10^10 = 0.693/(2.2 xx 10^9) xx "N"`

∴ N = `(2.2 xx 10^9 xx 10^10)/(0.693)`

= 3.17 × 10¹⁹