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The half life of radium is about 1600 year. Of 100 gram of radium existing now, 25g will remain unchanged after
Options
(a) 4800 year
(b) 6400 year
(c) 2400 year
(d) 3200 year
Correct Answer:
3200 year
Explanation:
100 gram at beginning, I = 0
25 gram remains undecayed.
N / N₀ = (1 / 2)ⁿ ⇒ 25 / 100 = (1 / 2)ⁿ
⇒ 1 / 4 = (1 / 2)ⁿ
Therefore, n = 2
Time = n × T
= 2 × 1600
= 3200 years.
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Topics: Radioactivity
(83)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- An ac voltage is applied to a resistance R and an inductor L in series
- One way in which the operation of a n-p-n transistor differs from that of a p-n-p
- Three resistances 2Ω, 3Ω and 4Ω are connected in parallel. The ratio of currents passing
- A car moving with a speed of 50 kmh⁻¹ can be stopped by brakes after at least 6 m
- A bottle full of water in a space ship at 30⁰C is carried on the moon.
Topics: Radioactivity (83)
Subject: Physics (2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
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