The mean life of an elementary particle pion is `2xx10^(-7)` ns. The age of the univers is about `4xx10^9` years. Identify a physically meaning time that is approximately half way between these two on a logarithmic scale.

The radius of a proton is about 10^(-9) micron and the radius of universe is about 10^(28) cm. Name a physical object whose size is approximately halfl way between these two extermes on a logarithmin scale.

The radioactive constant of radium is 4.28 xx 10^(-4) per year, its half period is approximately

If the age of some students are 6,10,5,4,9,11,20,18 years, then their mean age is

The decay constant of a radioactive material is 5 xx 10^(-4) per year.find its half-life period.

Half lives of two isotopes X and Y of a material are known to be 2 xx 10^(9) years and 4 xx 10^(9) years respectively. If a planet was formed with equal number of these isotopes, then the current age of planet, given that currently the material has 20 % of X and 80 % of Y by number, will be

Half lives of two isotopes X and Y of a material are known to be 2xx10^(9) years and 4xx10^(9) years respectively if a planet was formed with equal number of these isotopes, then the current age of planet, given that currently the material has 20% of X and 80% of Y by number, will be:

Half lives of two isotopes X and Y of a material are known to be 2xx10^(9) years and 4xx10^(9) years respectively if a planet was formed with equal number of these isotopes, then the current age of planet, given that currently the material has 20% of X and 80% of Y by number, will be:

Half lives of two isotopes X and Y of a material are known to be 2xx10^(9) years and 4xx10^(9) years respectively. If a planet forms with equal number of these isotopes, estimate the current age of the planet, given that currently the material has 20% of X and 80% of Y by number