Certain radioactive substance reduces to $25\%$ of its value in $16\ days$. Its half-life is .......... $days$
Certain radioactive substance reduces to $25\%$ of its value in $16\ days$. Its half-life is .......... $days$
- A
$32$
- B
$8$
- C
$64$
- D
$28$
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The count rate for $10\ g$ of radioactive material was measured at different times and this has been shown in the graph with scale given. The half life of the material and the total count in the first half value period respectively are
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Assertion : If the half life of a radioactive substance is $40\, days$ then $25\%$ substance decay in $20\, days$
Reason : $N = {N_0}\,{\left( {\frac{1}{2}} \right)^n}$
where, $n = \frac{{{\rm{time\, elapsed}}}}{{{\rm{half \,life \,period}}}}$
Assertion : If the half life of a radioactive substance is $40\, days$ then $25\%$ substance decay in $20\, days$
Reason : $N = {N_0}\,{\left( {\frac{1}{2}} \right)^n}$
where, $n = \frac{{{\rm{time\, elapsed}}}}{{{\rm{half \,life \,period}}}}$
- [AIIMS 1998]
Half lives of two radioactive nuclei $A$ and $B$ are $10\, minutes$ and $20\, minutes$, respectively. If, initially a sample has equal number of nuclei, then after $60$ $minutes$ , the ratio of decayed numbers of nuclei $A$ and $B$ will be
Half lives of two radioactive nuclei $A$ and $B$ are $10\, minutes$ and $20\, minutes$, respectively. If, initially a sample has equal number of nuclei, then after $60$ $minutes$ , the ratio of decayed numbers of nuclei $A$ and $B$ will be
- [JEE MAIN 2019]
A sample originally contaived $10^{20}$ radioactive atoms, which emit $\alpha -$ particles. The ratio of $\alpha -$ particles emitted in the third year to that emitted during the second year is $0.3.$ How many $\alpha -$ particles were emitted in the first year?
A sample originally contaived $10^{20}$ radioactive atoms, which emit $\alpha -$ particles. The ratio of $\alpha -$ particles emitted in the third year to that emitted during the second year is $0.3.$ How many $\alpha -$ particles were emitted in the first year?
- [AIEEE 2012]