Analysis of potassium and argon atoms in a moon rock sample by a mass spectrometer shows that the ratio of the number of stable `Ar^(40)` atoms present to the number of radioactive `K^(40)` atoms is 7 : 1 . Assume that all the argon were produced by the decay of potassium atoms, with a half-life of `1.25 xx 10^(9)` year. How old is the rock?

Mass spectrometic analysis of potassium and argon atoms in a Moon rock sample shows that the ratio of the number of (stable) .^(40) At atoms present to the number of (radioactive) .^(40)K atoms is 10.3 .Assume that all the argon atoms were produced by the decay of potassium atoms, with a half-life of 1.25 xx 10^(9) yr . How old is the rock ?

In a Moon rock sample the ratio of number of (stable) ""^(40)Ar atoms present to the number of (radioactive) ""^(40)K atoms is 10.3. Assume that all the argon atoms were produced by the decay of potassium atoms, with a half life of 1.25xx10^(9)y . How old is the rock?

In moon rock sample the ratio of the number of stable argon- 40 atoms present to the number of radioactive potassium -40 atoms is 7:1 . Assume that all the argon atoms were produced by the decay of potassium atoms, with a half-life of 2.5xx10^(9)yr . The age of the rock is

.^(238)U decays with a half-life of 4.5 xx10^(9) years, the decay series eventually ending at .^(206)Pb , which is stable. A rock sample analysis shows that the ratio of the number of atoms of .^(206)Pb to .^(238)U is 0.0058. Assuming that all the .^(206)Pb is produced by the decay of .^(238)U and that all other half-lives on the chain are negligible, the age of the rock sample is (ln 1.0058 =5.78 xx10^(-3)) .

.^(238)U decays with a half-life of 4.5 xx10^(9) years, the decay series eventaully ending at .^(206)Pb , which is stable. A rock sample analysis shows that the ratio of the number of atoms of .^(206)Pb to .^(238)U is 0.0058. Assuming that all the .^(206)Pb is prodduced by the decay of .^(238)U and that all other half-lives on the chain are negligilbe, the age of the rock sample is (1n 1.0058 =5.78 xx10^(-3)) .

For a radioactive sample, determine the ratio of the number of atoms decays of during the first half of its half- life to the number of atoms decays of during the second half of its half cycle.

The number of U^(238) nuclei in a rock sample equal to the number of Pb^(206) atoms. The half life of U^(238) is 4.5xx10^(9) years. The age of the rock is

The half-life of a sample of a radioactive substance is 1 hour. If 8 xx 10^10 atoms are present at t = 0 , then the number of atoms decayed in the duration t = 2 hour to t = 4 hour will be