# (a) Define the term decay constant of a radioactive substance.(b) The half life of undergoing decay is years. Calculate the activity of 10 g sample of .

a) The decay constant of a given radioactive sample is the constant of proportionality between its instantaneous decay rate and the total number of its decaying nuclei at that instant.

b)

$\\\lambda=\frac{0.693}{4.5\times10^{9}}years$

Number of atoms in 10g sample of $_{92}^{238}U$

$N=\frac{10}{238}\times6.02\times10^{23}\ atoms$

$\\R=\frac{0.693}{4.5\times10^{9}}\times\frac{10}{238}\times6.023\times10^{23}atoms/year\\\\R=1.24\times10^{7}atoms/sec$

## Related Chapters

### Preparation Products

##### Knockout NEET May 2023 (Easy Installments)

Personalized AI Tutor and Adaptive Time Table, Self Study Material, Weekend Live Classes, Mentorship from our Experts, Unlimited Mock Tests and Personalized Analysis Reports, 24x7 Doubt Chat Support,.

₹ 5499/-
##### Knockout JEE Main April 2021 (One Month)

Personalized AI Tutor and Adaptive Time Table, Self Study Material, Weekend Live Classes, Mentorship from our Experts, Unlimited Mock Tests and Personalized Analysis Reports, 24x7 Doubt Chat Support,.

₹ 14000/- ₹ 4999/-
##### Knockout NEET Aug 2021 (One Month)

Personalized AI Tutor and Adaptive Time Table, Self Study Material, Weekend Live Classes, Mentorship from our Experts, Unlimited Mock Tests and Personalized Analysis Reports, 24x7 Doubt Chat Support,.

₹ 14000/- ₹ 4999/-
##### Knockout JEE Main May 2021

Personalized AI Tutor and Adaptive Time Table, Self Study Material, Weekend Live Classes, Mentorship from our Experts, Unlimited Mock Tests and Personalized Analysis Reports, 24x7 Doubt Chat Support,.

₹ 22999/- ₹ 9999/-