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A radioactive substance has a half-life of four months. Three-fourth of substance will decay in
Options
(a) 3 months
(b) 4 months
(c) 8 months
(d) 12 months
Correct Answer:
8 months
Explanation:
Substance left undecayed N = N₀ – (3 / 4) N₀ = (1 /4) N₀
N / N₀ = (1 / 2)ⁿ
where n = number of half lives
.·. 1 / 4 = (1 / 2)ⁿ (or), n = 2 n = t / T₁/₂ t = nT₁/₂ = 2 × 4 = 8 months.
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Topics: Radioactivity
(83)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- A proton is projected with a speed of 3×10⁶ m/s horizontally from east to west.
- The magnifying power of a telescope is 9. When it is adjusted for parallel rays
- A short magnet of magnetic moment M, is placed on a straight line. The ratio
- A black body is heated from 27° C to 127° C. The ratio of their energies of radiations
- For the action of a common Base (CB) transistor, (E=emitter, B= base, C= collector)
Topics: Radioactivity (83)
Subject: Physics (2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
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