Q)
(chatquestion)...67 A sample of radioactive element has a mass of
10 g at an instant t = 0. The approximate mass of
this element in the sample after two mean lives is
(a) 1.35 g
(c) 3.70 g
(b) 2.50 g
(d) 6.30 g
(2003)
l the radius...(Please solve this)
...
