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The half life of a radioactive isotope ‘X’ is 20 years. It decays to another element ‘Y’ which is stable. The two elements ‘X’ and ‘Y’ were found to be in the ratio of 1 : 7 in a sample of a the given rock. The age of the rock is estimated to be
Options
(a) 60 years
(b) 80 years
(c) 100 years
(d) 40 years
Correct Answer:
60 years
Explanation:
The value of x is 1/8
= x₀/8 = x₀/2³ ⇒ t = 3t = 3 x 20 = 60 yrs
Hence the estimated age of rock is 60 yrs.
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Topics: Atoms and Nuclei
(136)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- In a potentiometer experiment two cells of e.m.f. E₁ and E₂ are used in series
- A bullet emerges from a barrel of length 1.2 m with a speed of 640 ms⁻¹.
- A coil has resistance 30 ohm and inductive reactance 20 ohmn at 50 Hz frequency.
- The ferromagnetic substance is
- An avarage induced e.m.f. of 1 V appears in a coil when the current in it is changed
Topics: Atoms and Nuclei (136)
Subject: Physics (2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
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