question_answer

A piece of wood from a recently cut tree shows 20 decays per minute. A wooden piece of same size placed in a museum (obtained from a tree cut many years back) shows 2 decays per minute. If half-life of is 5730 years, then age of the wooden piece placed in the museum is approximately:                    [JEE ONLINE 19-04-2014]

A) 10439 years

B) 13094 years

C) 19039 years

D) 39049 years

Correct Answer: C

Solution :

[c] Given: decays/min

decays/min

years

As we know,

But

= 19039 years