Physics · 2019
JEE Main · 9 January 2019, Shift 2 · Q26
At a given instant, say t =0, two radioactive substances A and B have equal activities. The ratio R_B/R_A of their activities after time t itself…
At a given instant, say $\displaystyle \mathrm{t}=0$, two radioactive substances A and B have equal activities.
The ratio $\displaystyle \frac{R_B}{R_A}$ of their activities after time t itself decays with time t as $\displaystyle \mathrm{e}^{-3 \mathrm{t}}$. If the half-life of A is ln2, the half-life of B is :
Official answer
(1)
$\displaystyle \frac{\ln 2}{4}$
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JEE Main 2019 Physics question, with the answer from NTA’s final answer key. Where our answers come from.