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प्रश्न
Define 'activity' of a radioactive substance ?
उत्तर
The total decay rate of a radioactive sample is called the activity of the sample. Its S.I. unit is Becquerel (Bq).
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संबंधित प्रश्न
State the law of radioactive decay.
How is the mean life of a given radioactive nucleus related to the decay constant?
Obtain the relation between the decay constant and half life of a radioactive sample.
The half-life of `""_38^90 "Sr"` is 28 years. What is the disintegration rate of 15 mg of this isotope?
Represent Radioactive Decay curve using relation `N = N_o e^(-lambdat)` graphically
Calculate the maximum kinetic energy of the beta particle emitted in the following decay scheme:
12N → 12C* + e+ + v
12C* → 12C + γ (4.43MeV).
The atomic mass of 12N is 12.018613 u.
(Use Mass of proton mp = 1.007276 u, Mass of `""_1^1"H"` atom = 1.007825 u, Mass of neutron mn = 1.008665 u, Mass of electron = 0.0005486 u ≈ 511 keV/c2,1 u = 931 MeV/c2.)
Before the year 1900 the activity per unit mass of atmospheric carbon due to the presence of 14C averaged about 0.255 Bq per gram of carbon.
(a) What fraction of carbon atoms were 14C?
(b) An archaeological specimen containing 500 mg of carbon, shows 174 decays in one hour. What is the age of the specimen, assuming that its activity per unit mass of carbon when the specimen died was equal to the average value of the air? The half-life of 14C is 5730 years.
'Half-life' of a radioactive substance accounts for ______.
What percentage of radioactive substance is left after five half-lives?
Draw a graph showing the variation of decay rate with number of active nuclei.
