Last Updated
：2025/11/21
potassium-40
Noun
uncountable
Japanese Meaning
自然に存在する放射性同位体で、⁴⁰₁₉Kと表記される。19個の陽子と21個の中性子を持ち、半減期は約13億年であり、生体内における自然放射能の主要な原因となるカリウムの一種
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(physics) A naturally-occurring radioactive isotope of potassium, ⁴⁰₁₉K, having nineteen protons and twenty-one neutrons, and a half-life of 1.3 billion years; it is the chief source of natural radioactivity in living tissue
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potassium-40
Measurements in rock samples showed traces of potassium-40, allowing geologists to estimate their age.
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Measurements in rock samples showed traces of potassium-40, allowing geologists to estimate their age.
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