The half-life of ``^198Au` is 2.7 days.(a) Find the activity of a sample containing `1.00 mu g ` of ``^198Au`.(b) What will be the activity after 7 days ? Take the atomic weight of ``198Au` to be `198 g mol^-1`.

Answer

A, B, C, D

Explanation

(a) We know that activity = `lambda n`
and Here `n = (1 xx 10^(-6) xx 6.023 xx 10^(23) )/(198) `
`= (6.023 xx 10^(17))/( 198) `
so , activity
` = (0.693 xx 10^(17) xx 6.023)/(27 xx 198 xx 24 xx 3600 ) xx ((1)/(37 xx 10^(10))Ci`
` = 0.244 Ci `
(b) We know that
` A = A_(8)e ^(-lambdatau) `
`= 0.244 xx e ^(0.698/(8) xx7 )`
` = 0.244 xx e^(-1.7966) `
`= 0.040 Ci`