Question

Which of the following isotopes is used for finding the fossil age maximum about $35,0000$ years?

• A. ${}^{238}U$
• B. ${}^{14}C$
• C. ${}^{3}H$
• D. $206Pb$

Answer 1

The correct option is A ${}^{238}U$

Half life of carbon-14 is approx. 5730 years, hence it can be used to determine the age of fossil upto 70,000 years.

Half life of U-238 is 4.5 billion years .

So, the correct option is '238U'