A experiment is done to determine that half life of a radiactive substance that emits one beta particle of each decays process Measurements show that an average of 8.4 beta particles are emitted each second by 2.5 milligram of the substance. The atomic weight of the substance is 230. Find the half life of the substance.

(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).

A radioactive substance decays to (3)/(4) th of original value in 2h. The half-life of the substance is

If 8g of a radioactive substance decays into 0.5 g in 1 h, then the half-life of the substance is

The half - life of a radioactive substance is 60 years. Calculate its decay constant given log e 2=6930

The half-life period of a radioactive substance is 5 min . The amount of substance decayed in 20 min will be

N atoms of a radioactive substance emit n alpha -particles per second. The half life of the radioactive substance is

Half life of a radioactive substance is 60 min. After 3 hours, the fraction of total number of atoms that have decayed would be