JEE Main 2023 · PhysicsMultiple choiceSingle correctEasyCalculation

JEE Main 15 April 2023, Shift 1, Physics Q44

Question 44 of 90 in this shift, Physics question 14 of 30, Section A.

The half-life of a radioactive nucleus is 5 years. The fraction of the original sample that would decay in 15 years is:

(1) $\frac{1}{4}$
(2) $\frac{1}{8}$
(3) $\frac{3}{4}$
(4) $\frac{7}{8}$ Official answer

Official answer

Option 4

NTA final key.

Chapter: Nuclei
Topic: Radioactive Decay
Idea tested: Half-Life Calculations

Same idea in other shifts

Asked 10× in all

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27 Jul 2022, Shift 2 · Q48The activity of a radioactive material is $6.4\times10^{-4}$ curie. Its half life is 5 days. The activity will become $5\times10^{-6}$ …EasySingle correct
29 Jun 2022, Shift 1 · Q33The activity of a radioactive material is $2.56 \times 10^{-3}$ Ci. If the half life of the material is 5 days, after how many days the…EasySingle correct
3 Aug 2021, Shift 2 · Q18A radioactive isotope has a half life of T years. After how much time is its activity reduced to 6.25% of its original activity ?EasySingle correct
3 Aug 2021, Shift 2 · Q25A sample undergoing beta decay, reduced to $\frac{1}{16}^{\mathrm{th}}$ of its initial mass in 48 years. Its half life period is…EasyNumerical value
27 Aug 2021, Shift 1 · Q19There are $10^{10}$ radioactive nuclei in a given radioactive element. Its half-life time is 1 minute. How many nuclei will remain after…EasySingle correct
16 Mar 2021, Shift 2 · Q10Calculate the time interval between 33% decay and 67% decay if half-life of a substance is 20 minutes.EasySingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.