Two radioactive isotopes P and Q have half Jives 10 minutes and 15 minutes respectively. Freshly pre

English

Gujarati

Hindi

13.Nuclei

medium

Two radioactive isotopes $P$ and $Q$ have half Jives $10$ minutes and $15$ minutes respectively. Freshly prepared samples of each isotope initially gontain the same number of atoms. After $30$ minutes, the ratio $\frac{\text { number of atoms of } P}{\text { number of atoms of } Q}$ will be

A

$0.5$

B

$2.0$

C

$1.0$

D

$3.0$

Solution

(a)

$T_P=10$ minute $\quad T_Q=15$ minute

After $30$ minute $P$ has gone $3$ half lives and $Q=2$ half lives

$N_P=N_0\left(\frac{1}{2}\right)^3$ $\quad N_Q=N_0\left(\frac{1}{2}\right)^2$

$N_P: N_Q=1: 2$

$\text { or } \frac{N_P}{N_Q}=0.5$

Standard 12

Physics

Share

Similar Questions

The half-life of a radioactive substance is $40$ years. How long will it take to reduce to one fourth of its original amount and what is the value of decay constant

medium

If half life of an element is $69.3$ hours then how much of its percent will decay in $10^{\text {th }}$ to $11^{\text {th }}$ hours. Initial activity $=50\, \mu Ci$

hard

(AIIMS-2019)

After five half lives what will be the fraction of initial substance

easy

The sun radiates energy in all directions. The average radiations received on the earth surface from the sun is $1.4\;kilowatt/{m^2}$.The average earth- sun distance is $1.5 \times {10^{11}}metres$. The mass lost by the sun per day is($1$ day $= 86400$ seconds)

medium

The decay constant of a radio isotope is $\lambda$. If $A_1$ and $A_2$ are its activities at times $t_1$ and $t_2$ respectively, the number of nuclei which have decayed during the time $(t_1 – t_2)$

easy

(AIPMT-2010)