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A radioactive element has half life of 4...

A radioactive element has half life of `4.5 xx 10^(9)` years. If `80 g` of this was taken, the time taken for it to decay to `40 g` will be
a. `2.25 xx 10^(9)` years b. `4.50 xx 10^(9)` years
c. `6.75 xx 10^(9)` years d. `8.75 xx 10^(9)` years

A

a. `2.25 xx 10^(9)` years

B

b. `4.50 xx 10^(9)` years

C

c. `6.75 xx 10^(9)` years

D

d. `8.75 xx 10^(9)` years

Text Solution

Verified by Experts

The correct Answer is:
B
`t_(1//2) = 4.5 xx 10^(9)` years
Here the amount decay to 50% i.e., from `80 g` to `40 g` Therefore time required will be `4.5 xx 10^(9)` years.
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