Q18.A radioactive material decays by simultaneous emissions of two particles with half lives of 1400 years and 700 years, respectively. What will be the time after the which one third of the material remains ? (Take ln 3 = 1. 1 ) (1) 1110 years (2) 700 years (3) 340 years (4) 740 years
What This Question Tests
This question tests the understanding of parallel radioactive decay, where an effective decay constant is used to calculate the time taken for a certain fraction of the material to remain.
Concepts Tested
Formulas Used
N = N₀ e^(-λt)
λ = ln(2)/T_½
λ_effective = λ₁ + λ₂
📚 NCERT Sections This Tests
3.17 — During Nuclear Explosion, One Of The Products Is 90Sr With Half-Life Of
Chemistry Class 11 · Chapter 3
3.17 During nuclear explosion, one of the products is 90Sr with half-life of 28.1 years. If 1mg of 90Sr was absorbed in the bones of a newly born baby instead of calcium, how much of it will remain after 10 years and 60 years if it is not lost metabolically.
3.18 — For A First Order Reaction, Show That Time Required For 99% Completion
Chemistry Class 11 · Chapter 3
3.18 For a first order reaction, show that time required for 99% completion is twice the time required for the completion of 90% of reaction.
13.4 — Obtain Approximately The Ratio Of The Nuclear Radii Of The Gold Isotope
Physics Class 12 · Chapter 13
13.4 Obtain approximately the ratio of the nuclear radii of the gold isotope 197 79 Au and the silver isotope 10747 Ag .
📋 Question Details
- Chapter
- Nuclei
- Topic
- Radioactive decay (parallel decay)
- Year
- 2021
- Shift
- 20 Jul Shift 1
- Q Number
- Q18
- Type
- MCQ
- NCERT Ref
- Class 12 Physics Ch 13: Nuclei
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