Half-life of a substance is 20 , minutes. Wha | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(B) Let $N_{0}$ be the initial number of radioactive nuclei.After $33 \%$ decay,the number of undecayed nuclei remaining is $N_{1} = N_{0} - 0.33 N_{0

Vedclass · Accepted Answer

$20$

Vedclass · Answer

(B) Let $N_{0}$ be the initial number of radioactive nuclei.After $33 \%$ decay,the number of undecayed nuclei remaining is $N_{1} = N_{0} - 0.33 N_{0} = 0.67 N_{0}$.After $67 \%$ decay,the number of undecayed nuclei remaining is $N_{2} = N_{0} - 0.67 N_{0} = 0.33 N_{0}$.We observe that $N_{2} \approx \frac{N_{1}}{2}$,since $0.33 N_{0} \approx \frac{0.67 N_{0}}{2}$.By the definition of half-life,the time required for the number of undecayed nuclei to reduce to half of its initial value is exactly one half-life.Therefore,the time taken for the substance to decay from $33 \%$ to $67 \%$ is equal to the half-life of the substance,which is $20 \, minutes$.

Half-life of a substance is $20 \, minutes$. What is the time between $33 \%$ decay and $67 \%$ decay? ................ $minutes$

Similar Questions

The half-life of $Ra^{226}$ is $1620$ years. Calculate the number of atoms that decay in one second in $1 \ g$ of radium (Avogadro number $= 6.023 \times 10^{23}$).

The rate of disintegration was observed to be $10^{17}$ disintegrations per second when its half-life period is $1445$ years. The original number of particles is:

The decay constant of a radioactive sample is $\lambda$. The probability of decay per unit time is:

Which one of the following nuclei has a shorter mean life?

$A$ radioactive sample consists of two distinct species having an equal number of $N_0$ atoms initially. The mean-life of one species is $\tau$ and of the other is $5\tau$. The decay products in both cases are stable. The total number of radioactive nuclei at $t = 5\tau$ is

Vedclass Test Series

Exam Paper Generator

Online Exam Module