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Problem
Problem
A radioactive element decays by
β
\beta
β
-emission. A detector records
n
n
n
beta particles in
2
s
2\,\text{s}
2
s
and in next
2
s
2\,\text{s}
2
s
it records
0.75
n
0.75n
0.75
n
beta particles. Find mean life correct to nearest whole number. Given
ln
2
=
0.6931
\ln 2 = 0.6931
ln
2
=
0.6931
,
ln
3
=
1.0986
\ln 3 = 1.0986
ln
3
=
1.0986
. (JEE 2003)
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