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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
- A light of wavelength 5000Å falls on a sensitive plate with photoelectric work
- An alternating electric field, of frequency v, is applied across the dees (radius = R)
- When a spring is extended by 2 cm energy stored is 100 J. When extended further by 2 cm
- The power factor of an AC circuit having resistance R and inductance L connected
- A polarised light of intensity I₀ is passed through another polariser whose pass axis
Topics: Atoms and Nuclei (136)
Subject: Physics (2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
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