Podcast Beta
Questions and Answers
What is the charge of a beta particle?
What type of radiation has the highest penetrating ability?
What is the main reason for the nucleus to be stable?
Who discovered radiation coming from uranium salts?
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What is the result of a nuclear reaction?
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What is the charge of a β particle?
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What is the purpose of radon barriers in new buildings?
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What is the use of carbon-14 in archaeology?
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What is the composition of an α particle?
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What is the purpose of Americium in smoke detectors?
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What happens to the carbon-14 in an organism when it dies?
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What type of radiation is emitted by Cobalt-60, used in cancer treatment?
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What is the purpose of irradiating food with Cobalt-60?
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Why is Americium-241 safe to use in smoke alarms?
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Why does the Americium-241 in a smoke alarm not need to be replaced?
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Study Notes
Radioactivity
- Radioactivity is the spontaneous breaking up of certain unstable nuclei, accompanied by the emission of radiation.
Causes of Radioactivity
- An unstable nucleus disintegrates when the ratio of protons to neutrons is not suitable.
- Fragments and energy are emitted from the nucleus as it tries to achieve stability.
History of Radioactivity
- Henri Becquerel discovered radiation coming from uranium salts in the late 1800's.
- Marie and Pierre Curie continued this work, discovering polonium and radium.
- Marie Curie won Nobel prizes in 1903 and 1911, but later died from exposure to radioactive substances.
Types of Radiation
- Three types of radiation: alpha (α), beta (β), and gamma (γ) particles.
Alpha Particles (α)
- Consist of 2 neutrons and 2 protons stuck together (helium nuclei).
- Have a + charge and weak penetrating ability.
- Can be stopped by human skin, but are hazardous if ingested or inhaled.
Beta Particles (β)
- Ejected from the nucleus when neutrons disintegrate into protons and electrons.
- Have a - charge and more penetrative ability than α particles.
- Can be stopped by 5mm of aluminum.
Gamma Rays (γ)
- High energy rays with no mass or charge.
- Have very high penetrating ability and can be damaging to human cells.
- Require thick shields of lead or concrete to stop.
Radioactive Decay
- Alpha decay: atomic number decreases by 2, mass number decreases by 4.
- Beta decay: atomic number increases by 1, mass number remains the same.
Half-Life
- Time taken for half the atoms in a sample of a radioactive isotope to decay.
- Example: Radium-214 has a half-life of 20 minutes.
Radioisotopes
- Isotopes are elements with the same atomic number but different mass numbers.
- Radioisotopes are unstable and undergo radioactive decay.
- Examples: Carbon-14 (unstable) and Carbon-12 (stable).
Uses of Radioisotopes
- Carbon dating: estimates the age of carbon-containing objects.
- Medicine: Cobalt-60 is used in cancer treatment.
- Food Preservation: Cobalt-60 is used to kill micro-organisms and insects in food.
- Smoke Alarms: Americium-241 is used to detect smoke.
Background Radiation
- A low level of radiation surrounds us at all times.
- Natural sources of radiation in the environment, mainly from radon gas emitted from rocks.
- Radon barriers are installed in new buildings to prevent the gas from seeping in.
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Description
Learn about the fundamentals of radioactivity, including the stable ratio of protons to neutrons in an atom's nucleus and the emission of radiation when this ratio is not met.
