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Mean lives of a radioactive substance are 1620 and 405 years for alpha and beta -emission respectively. If alpha and beta decays are simultaneous, then time during which three fourth of the sample will decay is : |
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Answer» 410 YEARS Also half-life period `T=0.93 tau=0.693 XX 324"years"` But `N/N_(0)=(1/2)^(l/T)` `1/R=(1/2)^(t//T) rArr (1/2)^(2) =(1/2)^(t//T) therefore t/t=2` `t=2T=2 xx 0.693 xx 324=449"years"` |
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