If the half lives of a radioactive element for `alpha` and `beta` decay are 4 year and 12 years respectively, then the percentage of the element that remains after 12 year will be

The half line of a radioactive element is 2n year. The fraction decayed in n year.

The number of nuclei of two radioactive substance is the same and their half-lives are 1 year and 2 years respectively. The ratio of their activities after 6 years will be

The number of nuclei of two radioactive substance is the same and their half-lives are 1 year and 2 years respectively. The ratio of their activities after 6 years will be

The mean lives of a radioactive material for alpha and beta radiations are 1620 and 520 years respectively . The material decays simultaneously for alpha and beta radiations. The time after which one fourth of the material remains undecayed in -

Mean life of a radioactive element is one year. Then its half life is (in year)

What is meant by pseudo unimolecular reaction. Explain with an example. 0.0625g remains from 1g of a radioactive element after 20 years of radioactive decay. Determine the rate constant and half-line (t1/2) of the reaction. How much of the element did remain after 10 years from the start.

Starting from 10g of a radioactive element, 0.25 g was left after 5 years. Calculate The time required for half of the element to decay.

The half lives of a radioactive sample are 30 years and 60 years from alpha- emission and beta- emission respectively. If the sample decays both by alpha- emission and beta- emission emission simultaneously, the time after which only one-fourth of the sample remain is