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Physics
Physics
Problem
For a radioactive sample with decay constant
λ
\lambda
λ
, which expression gives the time
t
t
t
required for the sample to decay to a fraction
f
f
f
of its initial activity? a)
t
=
ln
2
λ
ln
(
1
f
)
t = \dfrac{\ln 2}{\lambda}\,\ln\!\left(\dfrac{1}{f}\right)
t
=
λ
ln
2
ln
(
f
1
)
b)
t
=
1
λ
(
1
−
f
)
t = \dfrac{1}{\lambda}\,(1-f)
t
=
λ
1
(
1
−
f
)
c)
t
=
1
λ
ln
(
1
f
)
t = \dfrac{1}{\lambda}\,\ln\!\left(\dfrac{1}{f}\right)
t
=
λ
1
ln
(
f
1
)
d)
t
=
1
λ
ln
f
t = \dfrac{1}{\lambda}\,\ln f
t
=
λ
1
ln
f
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