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←, , antineutrino, , ←, , neutrino
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Law of Radioactive decay;, Statement; It states that the number of nuclei undergoing, radioactive decay per unit time is proportional to the total number, of nuclei in the sample., , This, , is called, , Decay, , Equation, , .
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Activity, , The rate of disintegration or number of disintegration’s per second in a, radioactive substance is known as Activity., I, , Negative sign shows that activity decreases with the passage of time., , R=, , -1¥
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Becquerel, , Decay constant ( X), we, , have, , off, X, , or, , =, , =, , -, , ✗N, , ¥7, N, , Decay constant is defined as the ratio of the amount of radioactive, substance which disintegrates in a unit time to the amount of, substances present., , Again, , N=, , ,, , No, , e-, , it, , if t=1×, then, , N, , =, , e- ¥, *, , No, , N=2N÷,g, , =, , =, , Noé, , ', , 0.37 No, , =, , Nog, or, , %-_ %, , of No, , So, decay constant of a radioactive substance is the reciprocal of, time during which the number of atoms left undecayed in the, sample reduces to 37% of the original number of atoms in the, sample.
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Half life of a radioactive substance, It is defined as the time during which half the number of atoms present, in a sample of radioactive substance will be left undecayed in the, sample. It is denoted by, , Ty, , ,, , Q. Find the relation between the half life and the decay constant, Ans: Suppose a radioactive substance has N 0 atoms at t= 0., Then the no.of atoms N left undecayed in the sample after time t is given, ✗t, by, N, ①, No e=, , when, , t, N, , Then, , her, , -, , =, , =, , ①, , Ti, , ,, , NI, becomes, , ¥, , =, , I, , =, , e-, , 2, , =, , e, , bn, , 2, , I, , +, , ✗I, , ✗%, , =, , ✗ Ty, , ,, , ✗, , i., , No e-, , =, , In, , 2, , I, , ✗, , Ty, , Stay life, , T, , ,, , =, , =, , =, , 0¥13, , 0.693, , 06,93T
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Average or mean life of a radioactive substance, , (Tav), , It is the sum of the lives of all the nuclei of the substance divided, by the total number of nuclei present initially in the substance., It is equal to the reciprocal of its decay constant., , Tav, , Relation, , =, , Tig, , between, , and, , Hay life, and, , :, , I, , mean, , ., , Ty, , life, =, , Tau, , =, , Tav, , 0-6×91, =, , 0.693, , I, Tau
