Source / pinned edition
Radioactive Decay
Source of package openstax.nuclear · OpenStax University Physics, ch. 10 Nuclear Physics, module m58609
- work
- urn:openstax:clir:nuclear#M58609
- number
- OpenStax University Physics, ch. 10 Nuclear Physics, module m58609
- kind
- urn:openstax:clir:nuclear#treatise
m58609/index.cnxml at commit d0ed34a (main, 2026-06-11)
- edition
- urn:openstax:clir:nuclear#M58609_MAIN
- language
- en
- officiality
- official
- materialisation
- PINNED_OFFICIAL_BYTES
- life cycle
- adopted: 2026-06-11
Publications
| URI | Type | documentHash | Retrieved |
|---|---|---|---|
| https://raw.githubusercontent.com/openstax/osbooks-university-physics-bundle/d0ed34a5851119a42e3d972dfc0ff49e4663977c/modules/m58609/index.cnxml | application/xml; charset=utf-8 | sha256:fdaebf73dbf4819517cc88b157460d245870b09505f320fb4305c197d454b781 | 2026-09-06T00:00:00Z |
Fragments — 8
module/m58609#fs-id1170901607045 · defn · referenced by: 1
en · official · sha256:a79b714d14d9af3fbef5ca6626c831c43f520f341f768114fef7be5fca957ceb
<definition id="fs-id1170901607045">
<term>activity</term>
<meaning id="fs-id1170901607051">magnitude of the decay rate for radioactive nuclides</meaning>
</definition>Referencing norms: ActivityIsLambdaTimesN
module/m58609#fs-id1170901607032 · defn
en · official · sha256:c2bd844ced47f78048371be055599a188c5fc7cfcd8966b46817e19d20a40f1d
<definition id="fs-id1170901607032">
<term>becquerel (Bq)</term>
<meaning id="fs-id1170901607038">SI unit for the decay rate of a radioactive material, equal to 1 decay/second</meaning>
</definition>module/m58609#fs-id1170901529353 · defn
en · official · sha256:9840c580f0040b5c30fbd8a5ec77cf92b02621526022b523047046d15c9edbf5
<definition id="fs-id1170901529353">
<term>decay</term>
<meaning id="fs-id1170901499142">process by which an individual atomic nucleus of an unstable atom loses mass and energy by emitting ionizing particles</meaning>
</definition>module/m58609#fs-id1170901499148 · defn · referenced by: 1
en · official · sha256:b3cac9048863346ab15dcc2fe516f7404a400a2776501d8ac7acff86df401f35
<definition id="fs-id1170901499148">
<term>decay constant</term>
<meaning id="fs-id1170901529329">quantity that is inversely proportional to the half-life and that is used in equation for number of nuclei as a function of time</meaning>
</definition>Referencing norms: decay_constant_per_second
module/m58609#fs-id1170901514233 · defn · referenced by: 6
en · official · sha256:03239f0f44fb7fbd3ac492274fb2539fbd3ce644be32b6c80fac46a28afd85fb
<definition id="fs-id1170901514233">
<term>radioactive decay law</term>
<meaning id="fs-id1170901514238">describes the exponential decrease of parent nuclei in a radioactive sample</meaning>
</definition>Referencing norms: ClaimedRemainingAgrees, ClaimedRemainingRefuted, RadioactiveDecayLaw, claimed_remaining, elapsed_seconds, initial_nuclei
module/m58609#fs-id1170902960891 · section
en · official · sha256:e6bd33ddd9bc9b5e10dfe361acebb2258798bc0dd3816ba1b5addd5c9bf7dcae
<note id="fs-id1170902960891">
<title>Radioactive Decay Law</title>
<para id="fs-id1170902957184">The total number <emphasis effect="italics">N</emphasis> of radioactive nuclei remaining after time <emphasis effect="italics">t</emphasis> is</para>
<equation id="fs-id1170902773953"><m:math><m:mrow><m:mi>N</m:mi><m:mo>=</m:mo><m:msub><m:mi>N</m:mi><m:mn>0</m:mn></m:msub><m:msup><m:mi>e</m:mi><m:mrow><m:mtext>−</m:mtext><m:mi>λ</m:mi><m:mi>t</m:mi></m:mrow></m:msup></m:mrow></m:math></equation>
<para id="fs-id1170901650724">where <m:math><m:mi>λ</m:mi></m:math> is the decay constant for the particular nucleus.</para>
</note>module/m58609#fs-id1170901529334 · defn · referenced by: 1
en · official · sha256:992d52c463a2325e1a3acf25d531b7306c273908e43d038c801d77f4f4a97bed
<definition id="fs-id1170901529334">
<term>half-life</term>
<meaning id="fs-id1170901571606">time for half of the original nuclei to decay (or half of the original nuclei remain)</meaning>
</definition>Referencing norms: HalfLifeIsLnTwoOverLambda
module/m58609#fs-id1170901602867 · section
en · official · sha256:79b6e73192264feab5798a7819966c4f8b156e2261541b4ff9d33c02dff1fd9c
<para id="fs-id1170901602867">The <term id="term-00006">half-life</term> <m:math><m:mrow><m:mrow><m:mo>(</m:mo><m:mrow><m:msub><m:mi>T</m:mi><m:mrow><m:mn>1</m:mn><m:mtext>/</m:mtext><m:mn>2</m:mn></m:mrow></m:msub></m:mrow><m:mo>)</m:mo></m:mrow></m:mrow></m:math> of a radioactive substance is defined as the time for half of the original nuclei to decay (or the time at which half of the original nuclei remain). The half-lives of unstable isotopes are shown in the chart of nuclides in <link target-id="CNX_UPhysics_43_01_Nuclides" document="m58607"/>. The number of radioactive nuclei remaining after an integer (<emphasis effect="italics">n</emphasis>) number of half-lives is therefore</para>The hash beside the text is the sha256 of its exact bytes. It is the check that the text shown matches the one pinned in the package: a divergence fails the oracle’s static analysis.