A radioactive isotope X with half life `1.5 xx 10^9 `yrs, decays into a stable nucleus Y. A rock sample contains both elements X and Y in ratio 1:15. Find the age of the rock.

A radioactive isotope X with half-life 1.5xx10^9 y decays into a stable nucleus Y. A rock sample contains both elements X and Y in ratio 1:15. Find the age of the rock .

A radioisotope Y with half-life 1.4xx10^9 years decays to X which is stable. A sample of the rock from a cave was found to contain X and Y in the ratio 1:7 . The age of the rock is - (A) 1.96 × 10^9 years. (B) 3.92 × 10^9 years. (C) 4.20 × 10^9 years. (D) 8.40 × 10^9 years.

The half-life of a radioactive isotope X is 50 years . It decays to another element Y which is stable . The two elements X and Y were found to be in the ratio of 1:15 in a sample of a given rock. The age of the rock was estimated to be

A radioactive sample of half-life 30 d contains 10^12 particles at an instant of time. Find the activity of the sample.

Two radioactive nuclei P and Q in a given sample decay into a stable nucleus R. At time t=0, number of P species are 4N_0 and that of Q are N_0 . Half-life of P (for conversion to R) is 1 min whereas that of Q is 2min. Initially there are no nuclei of R present in the sample. When number of nuclei of P and Q are equal, the number of nuclei of R present in the sample would be

The half-life of At^215 is 100 mus .The time taken for the radioactivity of a sample of the element to decay 1/16 th of its initial value is

The mean life of a radioactive element is 13 days. Initially a sample contains 1 g of this element . The mass of the element will be 0.5 g after a time of

The radioactive decay constant is 4.28 xx 10^-4 year^-1 . What is the half life period of it?

A first order reaction is found to have a rate constant, k= 5.5 xx 10^-14 s^-1 .Find the half-life of the reaction.

A first order reaction is found to have a rate constant, k=5.5xx10^(-14)s^(-1) . Find the half-life of the reaction.