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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
- Two springs with spring constants K₁=1500 N/m and K₂=3000 N/m
- A particle covers half of its total distance with speed v1 and the rest half distance
- An automobile engine develops 100 kW when rotating at a speed of 1800 rev/min
- When a piece of metal is illuminated by a monochromatic light of wavelength λ,
- An aicraft executes a horizontal loop of radius 1 km with a speed of 900 kmh⁻¹
Topics: Radioactivity (83)
Subject: Physics (2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
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