Answer 5_3_1

A sample of living material contains carbon 14 with an activity of 260 Bq kg-1.  What is the decay constant? (The fraction that is made of carbon-14 is 1.4 ´ 10-12)

 

No of particles = 1000 × 6 × 1023 ´ 1.4 ´ 10-12 = 7 × 1013 (P)

                                  12

 

 

Use DN/Dt = -lN (P)

 

-260 = -l × 7 × 1013

 

l = 3.7 × 20-12 s-1 (P)

 

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