Question

Half life of U-238 undergoing a decay is 4.5 × 10⁹ years. What is the activity of one gram of U-238 sample?

Answer 1

T_1/2 = 4.5 × 10⁹ years 

= 4.5 × 10⁹ × 365 × 24 × 60 × 60 

T_1/2 = 1.419 × 10¹⁷nsec.

Number of atoms in lg of U-238

Decay rate or activity A = λN but

A = 1.235 × 10⁴ Bq