Calculate the activity of one gm sample of `._(38)^(90)Sr` whose half life period is 28.8 years.

(a) Calculate the activity of one mg sample ._(28^(Sr^(90))) whose half life period is 28 years. (b) An experiment is performed to determine the half-life of a radioactive substance which emits one beta particle for each decay process. Observation shown that an average of 8.4 beta- particles are emitted each second by 2.5 mg of the substance. the atomic weight of the substance is 230 . calculate the half0life of the substance. (c) Determine the quantity of ._(84^(Po^(210))) necessary to provide a source of alpha particle of 5mCi strength ( T_(1//2) for Po = 138 day).

Calculate the average life of a radioactive substance whose half life period is 1650 years.

Calculate the average life of a radioactive substance whose half-life period is 100 years.

Calculate the specific activities of Na^(24) & U^(235) nuclides whose half lives are 15 hours and 7.1xx10^(8) years respectively.

The radium and uranium atoms in a sample of uranium mineral are in the ratio of 12.8xx10^(6) . If half life period of radium is 1620 years , the half life period of uranium will be

The activity of a sample of Ti(Z=22) decreased by 90% over a period of 10 years . The half life of the sample is

During nuclear explosion, one of the products is .^(99)Sr with half - life of 28.1 years. If 1 mug of .^(90)Sr was absorbed in the bones of a newly born baby instead of calcium, how much of its will remain after 10 years and 60 years if it is not lost metabolically.