110?
cos' M rxtnt~M product
10 gms of 57Co kept in an open container beta-decays with a half life of 270 days. The wt. of the material inside the container after 540 days will be very nearly
(A) 10 g
(B) 5 g
(C) 2.5 g
(D) 1.25 g
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7 Answers
1Since " T 1 / 2 " = 270 days , and given time = 540 days = T1 / 22
So , the required amount of Co = 14 . 10 gms = 2 . 5 gms
1If you are asking about the total weight of the inside the container after 540 days , then it would be 10 gms due to mass conservation . If you are asking the remaining weight of Co , then the answer is 2 . 5 gms .
1But that energy factor only comes into play if there is at all a difference in mass of products as compared to mass of reactants . Since in the question , no energy factor is mentioned , so I guess you don ' t have to think about energy .