`4xx10^23`tritium atoms are contained in a vessel. The half-life of decay of trituim nuclei is 12.3 y. Find (a) the activity of the sample ,(b) the number of decays in the next 10 hours (c ) the number of decays in the next 6.15 y.

Answer

A, B, C, D

Explanation

Given `N = 4 xx 10^(23) `
`t_(1/2) = 12.3 year `
`Activity = (dN)/(dt) `
` lambda n = (0.693)/(t_(1/2))N `
` = (0.693)/(12.3) XX 4 XX 10^(23) dis//year `
` = (0.693 xx 4 xx 10^(23))//(12.3 xx 3600 xx 24 xx 365 )) dis//sec`
` = 7.146 xx 10^(14) dis//sec `
` (b) `(dN)/( dt) = 7.146 xx 10^(14) `
No or decays in next 10 hrs.
` = 7.146 xx 10^(14) xx 10 xx 3600 `
` = 257.256 xx 10^(17) = 2.75 xx 10^(19) `
` (c) N = N _( 0) e^(lambda t ) = 2.82 xx 10^(23) `
= No of atoms remained
No of atons disintegrated
` = (4 - 2.82) xx 10^(23) = 1.18 xx 10^(23) `