The decay constant of sodium (Na) is 0.0000128 /s. The half-life of sodium is:
Correct answer: A. 15 hrs
- A. 15 hrs
- B. 16 hrs
- C. 900 s
- D. 3600 s
Explanation
The half-life (t1/2) of a substance is related to its decay constant (λ) by the following equation:t1/2 = ln(2) / λwhere:ln(2) = natural logarithm of 2 ≈ 0.693Given:λ = 0.0000128/sSubstituting the value, we get:t1/2 = 0.693 / 0.0000128t1/2 ≈ 54,000 sConverting seconds to hours:t1/2 ≈ 54,000 s / 3600 s/h ≈ 15 hoursHowever, this is not among the options. Let's recheck the calculation:t1/2 ≈ 0.693 / 0.0000128t1/2 ≈ 54,000 s / 10,800 s/h ≈ 5 hours
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