Radioactivity
Übersicht
Radioactivity is happening all around you right now: faint radiation from rocks, the air, your food and even outer space passes through you every second. Unstable nuclei throw out radiation at random, and learning to identify and measure it is the heart of nuclear physics.
In this lesson you will learn what background radiation is and where it comes from, how radiation is detected and counted, and the nature, ionising effect and penetrating power of alpha, beta and gamma radiation. You will also see how they behave in electric and magnetic fields and how to correct a count rate for background.
Ziele
- Know what is meant by background radiation
- Know the sources that make a significant contribution to background radiation including: (a) radon gas (in the air) (b) rocks and buildings (c) food and drink (d) cosmic rays
- Know that ionising nuclear radiation can be measured using a detector connected to a counter
- Use count rate measured in counts / s or counts / minute
- Describe the emission of radiation from a nucleus as spontaneous and random in direction
- Identify alpha (α), beta (β) and gamma (γ) emissions from the nucleus by recalling: (a) their nature (b) their relative ionising effects (c) their relative penetrating abilities (β+ are not included, β-particles will be taken to refer to β-)
- [Supplement] Use measurements of background radiation to determine a corrected count rate
- [Supplement] Describe the deflection of α-particles, β-particles and γ-radiation in electric fields and magnetic fields
- [Supplement] Explain their relative ionising effects with reference to: (a) kinetic energy (b) electric charge
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Unterrichtsbewertung
Herzlichen Glückwunsch zum Abschluss der Lektion über Radioactivity. Jetzt, da Sie die wichtigsten Konzepte und Ideen erkundet haben,
Sie werden auf eine Mischung verschiedener Fragetypen stoßen, darunter Multiple-Choice-Fragen, Kurzantwortfragen und Aufsatzfragen. Jede Frage ist sorgfältig ausgearbeitet, um verschiedene Aspekte Ihres Wissens und Ihrer kritischen Denkfähigkeiten zu bewerten.
Nutzen Sie diesen Bewertungsteil als Gelegenheit, Ihr Verständnis des Themas zu festigen und Bereiche zu identifizieren, in denen Sie möglicherweise zusätzlichen Lernbedarf haben.
- Which is a source of background radiation? A. radon gas B. a torch battery C. a magnet D. sound waves Answer: A
- Alpha radiation is best described as: A. an electron B. a helium nucleus C. an electromagnetic wave D. a proton Answer: B
- Which radiation is stopped by a few millimetres of aluminium? A. alpha B. beta C. gamma D. none of them Answer: B
- Which radiation is NOT deflected by a magnetic field? A. alpha B. beta C. gamma D. all are deflected equally Answer: C
- A counter reads 90 counts/s near a source; background is 10 counts/s. The corrected count rate is: A. 100 counts/s B. 80 counts/s C. 9 counts/s D. 10 counts/s Answer: B
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Weiterlernen mit offenen Quellen
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Lehrbuchabschnitt
Nuclear Radioactivity
The discovery and study of nuclear radioactivity quickly revealed evidence of revolutionary new physics. In addition, uses for nuclear radiation also emerged quickly—for example, people such as Ernest Rutherford used it to determine the size of the nucleus and devices were painted with radon-doped p
"College Physics: Nuclear Radioactivity" by OpenStax, OpenStax, Rice University, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source: https://openstax.org/books/college-physics/pages/31-1-nuclear-radioactivity. Access for free at https://openstax.org/books/college-physics/pages/1-introduction
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Lehrbuchabschnitt
Radiation Detection and Detectors
It is well known that ionizing radiation affects us but does not trigger nerve impulses. Newspapers carry stories about unsuspecting victims of radiation poisoning who fall ill with radiation sickness, such as burns and blood count changes, but who never felt the radiation directly. This makes the d
"College Physics: Radiation Detection and Detectors" by OpenStax, OpenStax, Rice University, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source: https://openstax.org/books/college-physics/pages/31-2-radiation-detection-and-detectors. Access for free at https://openstax.org/books/college-physics/pages/1-introduction
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