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AP EAMCET Engineering 22 Sep 2020 Shift 2 Paper
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© examsnet.com
Question : 97
Total: 160
If
75
%
of a radioactive sample disintegrates in
16
days, the half-life of the radioactive sample is __________ days.
6
4
8
12
Validate
Solution:
If
N
0
be the initial amount of radioactive sample, then after
t
=
16
day, remaining amount,
N
=
N
0
−
75
%
of
N
0
=
N
0
−
75
ln
0
N
0
=
N
0
4
Since, we know that,
N
=
N
0
(
1
2
)
n
⇒
N
0
4
=
N
0
(
1
2
)
n
⇒
1
4
=
(
1
2
)
n
⇒
(
1
2
)
2
=
(
1
2
)
n
⇒
n
=
2
⇒
t
T
1
/
2
=
?
⇒
16
T
1
/
2
=
2
⇒
T
1
/
2
=
16
2
=
8
days
© examsnet.com
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