The half-life of a radioactive substance is 3 | 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 nuclei at time $t=0$.$N_{1}$ is the number of remaining nuclei after $40\%$ decay:$N_{1} = (1 - 0.40) N_{0} =

Vedclass · Accepted Answer

$60$

Vedclass · Answer

(B) Let $N_{0}$ be the initial number of nuclei at time $t=0$.$N_{1}$ is the number of remaining nuclei after $40\%$ decay:$N_{1} = (1 - 0.40) N_{0} = 0.6 N_{0}$$N_{2}$ is the number of remaining nuclei after $85\%$ decay:$N_{2} = (1 - 0.85) N_{0} = 0.15 N_{0}$Now,find the ratio of remaining nuclei:$\frac{N_{2}}{N_{1}} = \frac{0.15 N_{0}}{0.6 N_{0}} = \frac{1}{4} = \left(\frac{1}{2}ight)^{2}$Since $\frac{N_{2}}{N_{1}} = \left(\frac{1}{2}ight)^{n}$,where $n$ is the number of half-lives,we have $n = 2$.Therefore,the time taken is $t = n 	imes T_{1/2} = 2 	imes 30 	ext{ minutes} = 60 	ext{ minutes}$.

The half-life of a radioactive substance is $30$ minutes. The time (in minutes) taken between $40\%$ decay and $85\%$ decay of the same radioactive substance is

Similar Questions

An element $X$ with a half-life of $1.4 \times 10^9$ years decays to form another stable element $Y$. $A$ sample is taken from a rock that contains both $X$ and $Y$ in the ratio $1:7$. If at the time of formation of the rock,$Y$ was not present in the sample,then the age of the rock in years is

Half-life period of a sample is $15$ years. How long will it take to decay $96.875\%$ of the sample?

The half-life of $_{38}^{90} Sr$ is $28$ years. What is the disintegration rate of $15 \; mg$ of this isotope?

After $1$ hour,$1/16$ of the radioactive substance remains. Its half-life is ....... minutes.

After five half-lives, the percentage of original radioactive atoms left is ...... $ \%$

Vedclass Test Series

Exam Paper Generator

Online Exam Module