Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • Engineering
  • A radioactive sample has half life of 5 days. To decay from 8 microcurie to 1 microcurie, the number of days taken will be:Option: 1 40</d

A radioactive sample has half life of 5 days. To decay from 8 microcurie to 1 microcurie, the number of days
taken will be:

Option: 1

40


Option: 2

25


Option: 3

15


Option: 4

10


Answers (1)

best_answer

Here,

Half life,  T_{1 / 2}=5 days 

Initial activity, \mathrm{R}_0=1 microcurie 

Final activity, \mathrm{R}=8 microcurie 

As  \frac{\mathrm{R}}{\mathrm{R}_0}=\left(\frac{1}{2}\right)^{\mathrm{n}} where \mathrm{n} is the no. of half lives 

\therefore\left(\frac{1}{8}\right)=\left(\frac{1}{2}\right)^{\mathrm{n}} \quad \text { or } \quad\left(\frac{1}{2}\right)^3=\left(\frac{1}{2}\right)^{\mathrm{n}} \quad \text { or } \quad \mathrm{n}=3

\text { As } \mathrm{n}=\frac{\mathrm{t}}{\mathrm{T}_{1 / 2}}               \text { or } \quad \mathrm{t}=\mathrm{nT}_{1 / 2}=(3)(5 \text { days })=15 \text { days }

Posted by

Info Expert 30

View full answer

JEE Main high-scoring chapters and topics

Study 40% syllabus and score up to 100% marks in JEE

Similar Questions

Trending Articles/News

anam-khan

JEE Main 2026 Registration LIVE: NTA session 1 form link at jeemain.nta.nic.in; application deadline
anam-khan

JEE 2026: IIT admissions show major shift toward AI, data science, away from core engineering courses
anam-khan

JEE Main 2026: NIT Delhi cut-offs for BTech courses show ever-increasing demands for AI, computer skills

Latest Question