A) 120 min
B) 60 min
C) 30 min
D) 15 min
Correct Answer: C
Solution :
Here, mass left after 2 hours \[=N=\frac{{{N}_{0}}}{16}\] (where \[{{N}_{0}}\] is the original mass) Time taken = 2 hours = 120 minute Using the relation \[N={{N}_{0}}\times {{\left( \frac{1}{2} \right)}^{n}}\] or \[\frac{{{N}_{0}}}{16}={{N}_{0}}\times {{\left( \frac{1}{2} \right)}^{n}}\] or \[\left( \frac{1}{16} \right)={{\left( \frac{1}{2} \right)}^{n}}\] \[{{\left( \frac{1}{2} \right)}^{4}}={{\left( \frac{1}{2} \right)}^{n}}\] so \[n=4\] Hence, half life period \[=\frac{120}{4}\] \[=30min\]You need to login to perform this action.
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