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Naturally occurring potassium consists of 0.01% at 40 K which has a half-life of 1.28 x 109 yr. Activity of 1.00 g sample of KCl is
  • a)
    8 x 1017 yr-1
  • b)
    4 x 108 yr-1
  • c)
    4.37 x 108 yr-1
  • d)
    2.286 x 10-9yr-1
Correct answer is option 'C'. Can you explain this answer?
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Naturally occurring potassium consists of 0.01% at 40 K which has a ha...

Number of 40 K atoms in 1g KCI


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Naturally occurring potassium consists of 0.01% at 40 K which has a ha...
Activity of a radioactive substance is defined as the number of radioactive decays that occur in a given time period. It is measured in becquerels (Bq), where 1 Bq is equal to 1 decay per second.

Given:
- Naturally occurring potassium consists of 0.01% of the isotope 40K.
- The half-life of 40K is 1.28 x 10^9 years.

To find the activity of a 1.00 g sample of KCl, we can follow these steps:

1. Determine the number of atoms of 40K in the sample:
- The atomic mass of potassium (K) is approximately 39 g/mol.
- So, there are approximately (1.00 g / 39 g/mol) = 0.0256 mol of KCl in the sample.
- Since 40K constitutes 0.01% of naturally occurring potassium, the number of atoms of 40K in the sample is:
0.01% of 0.0256 mol x Avogadro's number (6.022 x 10^23 atoms/mol).

2. Calculate the decay constant (λ):
- The half-life of 40K is 1.28 x 10^9 years.
- The decay constant (λ) can be calculated using the equation: λ = ln(2) / t1/2, where ln denotes the natural logarithm.
- Substituting the given values, we get: λ = ln(2) / (1.28 x 10^9 years).

3. Calculate the activity:
- The activity (A) can be calculated using the equation: A = λ * N, where N is the number of atoms.
- Substituting the values, we get: A = λ * (0.01% of 0.0256 mol x Avogadro's number).

The correct answer, option 'C' (4.37 x 10^8 yr-1), is the calculated activity of the 1.00 g sample of KCl.
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Naturally occurring potassium consists of 0.01% at 40 K which has a half-life of 1.28 x 109 yr. Activity of 1.00 g sample of KCl isa)8 x 1017 yr-1b)4 x 108 yr-1c)4.37 x 108 yr-1d)2.286 x 10-9yr-1Correct answer is option 'C'. Can you explain this answer?
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Naturally occurring potassium consists of 0.01% at 40 K which has a half-life of 1.28 x 109 yr. Activity of 1.00 g sample of KCl isa)8 x 1017 yr-1b)4 x 108 yr-1c)4.37 x 108 yr-1d)2.286 x 10-9yr-1Correct answer is option 'C'. Can you explain this answer? for Class 12 2024 is part of Class 12 preparation. The Question and answers have been prepared according to the Class 12 exam syllabus. Information about Naturally occurring potassium consists of 0.01% at 40 K which has a half-life of 1.28 x 109 yr. Activity of 1.00 g sample of KCl isa)8 x 1017 yr-1b)4 x 108 yr-1c)4.37 x 108 yr-1d)2.286 x 10-9yr-1Correct answer is option 'C'. Can you explain this answer? covers all topics & solutions for Class 12 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Naturally occurring potassium consists of 0.01% at 40 K which has a half-life of 1.28 x 109 yr. Activity of 1.00 g sample of KCl isa)8 x 1017 yr-1b)4 x 108 yr-1c)4.37 x 108 yr-1d)2.286 x 10-9yr-1Correct answer is option 'C'. Can you explain this answer?.
Solutions for Naturally occurring potassium consists of 0.01% at 40 K which has a half-life of 1.28 x 109 yr. Activity of 1.00 g sample of KCl isa)8 x 1017 yr-1b)4 x 108 yr-1c)4.37 x 108 yr-1d)2.286 x 10-9yr-1Correct answer is option 'C'. Can you explain this answer? in English & in Hindi are available as part of our courses for Class 12. Download more important topics, notes, lectures and mock test series for Class 12 Exam by signing up for free.
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