SATHEE: Nuclei - Result Question 62

Nuclei - Result Question 62

63. A radio isotope ’ $X$ ’ with a half life $1.4 \times 10^{9}$ years decays to ’ $Y$ ’ which is stable. A sample of the rock from a cave was found to contain ’ $X$ ’ and ’ $Y$ ’ in the ratio $1 : 7$ . The age of the rock is: [2014]

(a) $1.96 \times 10^{9}$ years

(b) $3.92 \times 10^{9}$ years

(d) $8.40 \times 10^{9}$ years

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Answer:

Correct Answer: 63. (c)

Solution:

$\begin{aligned} (c) A s \frac{N_{x}}{N_{y}} = \frac{1}{7} (Given) \\ \Rightarrow \frac{N_{x}}{N_{x} + N_{y}} = \frac{1}{8} = (\frac{1}{2})^{3} \end{aligned}$

Therefore, age of the rock $t = 3 T_{1 / 2} = 3 \times 1.4 \times 10^{9} y r s = 4.2 \times 10^{9} y r s$ .

Nuclei - Result Question 62

63. A radio isotope ’ $X$ ’ with a half life $1.4 \times 10^{9}$ years decays to ’ $Y$ ’ which is stable. A sample of the rock from a cave was found to contain ’ $X$ ’ and ’ $Y$ ’ in the ratio $1 : 7$ . The age of the rock is: [2014]

Answer:

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Nuclei - Result Question 62

63. A radio isotope ’ X ’ with a half life 1.4×109 years decays to ’ Y ’ which is stable. A sample of the rock from a cave was found to contain ’ X ’ and ’ Y ’ in the ratio 1:7. The age of the rock is: [2014]

Answer:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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63. A radio isotope ’ $X$ ’ with a half life $1.4 \times 10^{9}$ years decays to ’ $Y$ ’ which is stable. A sample of the rock from a cave was found to contain ’ $X$ ’ and ’ $Y$ ’ in the ratio $1 : 7$ . The age of the rock is: [2014]