Question Answers

Sahay Sir > Question Answers > Cengage NEET by C.P Singh > Part 2 > Chapter 14 - Nuclear Physics and Radioactivity > A radioactive isotope X with a half-life of 1.37×10^9 years decays to Y which is stable. A sample of rock from the moon was found to contain both the elements X and Y which were in the ratio of 1:7. The age of the rock is.

A radioactive isotope X with a half-life of 1.37×10^9 years decays to Y which is stable. A sample of rock from the moon was found to contain both the elements X and Y which were in the ratio of 1:7. The age of the rock is.

90% of the active nuclei present in a radioactive sample are found to remain undecayed after 1 day. The percentage of undecayed nuclei left after two days will be