If a radioactive element having half-life of 30 min is undergoing beta decay, the fraction of radioactive element remains undecayed after 90 min. will be

Question

If a radioactive element having half-life of 30 min is undergoing beta decay, the fraction of radioactive element remains undecayed after 90 min. will be (A) (1/8) (B) (1/2) (C) (1/4) (D) (1/16)

Tardigrade Admin · Accepted Answer

( N / N 0)=((1/2)) t /t (1/2)=((1/2))(90/30) ( N / N 0)=((1/2))3=(1/8)

Q. If a radioactive element having half-life of $30 min$ is undergoing beta decay, the fraction of radioactive element remains undecayed after $90 min$ . will be

$\frac{1}{8}$

$\frac{1}{2}$

$\frac{1}{4}$

$\frac{1}{16}$

$\frac{N}{N _{0}} = (\frac{1}{2})^{t / t \frac{1}{2}} = (\frac{1}{2})^{\frac{90}{30}}$
$\frac{N}{N _{0}} = (\frac{1}{2})^{3} = \frac{1}{8}$

Q. If a radioactive element having half-life of 30min is undergoing beta decay, the fraction of radioactive element remains undecayed after 90min. will be

81​

21​

41​

161​