Question

$N_1$ atoms of a radioactive element emit $N_2\beta$-particles per second. The decay constant of the elements is (in $s^{-1})$

• A. $\frac{N_1}{N_2}$
• B. $\frac{N_2}{N_1}$
• C. $N_{1}ln\left(2\right)$
• D. $N_{2}ln\left(2\right)$

Answer 1

The correct option is B $\frac{N_2}{N_1}$

$\frac{d{N}_1}{dt}=-N_2$
Assuming first order decay of $N_1$
$\frac{d{N}_1}{dt}=-\lambda N_1$
$N_2=\lambda N_1$