C4- Radiation Flashcards
(31 cards)
Radioactivity
Radioactivity is defined as the spontaneous decay of a radioactive nucleus, whereby it emits one or more forms of nuclear radiation.
Its the name given to a stream of particles or electromagnetic rays emitted during nuclear decay.
Terrestrial Raditaion
FROM THE EARTH- This radiation is emitted by the large number of radioactive nuclei emitting radiation from the Earth’s crust and the atmosphere
it can be natrual or artificial
Cosmic Radiation
FROM SAPCE- The atmosphere and the Earth’s magnetic field protect us from most cosmic radiation.
Alpha Decay
Alpha Decay is a type of radioactive decay where an unstable atomic nucleus emits an alpha particle (α) to become more stable.
Change in Atomic Number: The atomic number decreases by 2 (because 2 protons are lost).
Change in Mass Number: The mass number decreases by 4 (because 2 protons and 2 neutrons are lost).
2 protons + 2 nuetrons = overall mass loss of 4
Alpha Decay- PROPERTIES
As alpha particles have a charge of +2, they tend to attract electrons from nearby atoms and cause these atoms to ionise readily.
- Low penetrating power (stopped by paper or skin).
- High ionizing power (can cause damage if ingested or inhaled).
- Occurs in heavy elements (e.g., Uranium, Thorium).
- Speed: ~5-7% of the speed of light. (slowest )
- Dangerous when inhaled or ingested, not harmful externally.
Beta Decay
an unstable nucleus transforms by emitting a beta particle (a fast-moving electron or positron) and a neutrino or antineutrino. It occurs when a neutron in the nucleus changes into a proton and an electron, maintaining charge balance.
The electron (β⁻ particle) is emitted, while the proton remains in the nucleus, increasing the atomic number (Z) by 1, while the atomic mass remains unchanged.
Beta Decay- PROPERTIES
- Emits a beta particle (electron, β⁻).
- Increases atomic number by 1, mass number remains the same.
- Moderate penetrating power (can pass through paper, blocked by thin metal).
- Moderate ionizing power.
- Occurs in unstable nuclei (e.g., Carbon-14, Strontium-90).
- Speed: Close to the speed of light. (99%)
- External exposure can be harmful, but less damaging than alpha radiation.
Gamma Decay
Gamma decay is a type of radioactive decay in which an unstable nucleus releases gamma radiation in the form of high-energy electromagnetic waves (gamma rays).
Gamma decay typically occurs after alpha or beta decay, as the nucleus moves from a high-energy state to a more stable, lower-energy state. Unlike alpha and beta decay, gamma decay does not change the number of protons or neutrons in the nucleus, so it does not alter the atomic number (Z) or atomic mass. Gamma rays have no charge and high penetrating power, making them more difficult to shield against compared to alpha and beta particles.
Gamma Decay-Properties
- Emits gamma rays (high-energy electromagnetic waves).
- No change in atomic or mass numbers.
- High penetrating power (requires thick lead or concrete to block).
- Low ionizing power.
- Typically follows alpha or beta decay to release excess energy.
- Speed: Speed of light.
- External exposure can be harmful, especially at high doses.
What is meant by Ionising?
- Ionising refers to the ability of radiation to remove electrons from atoms, creating charged particles (ions).
- Ionising radiation includes alpha, beta, and gamma radiation.
- It can cause damage to living cells, leading to mutations or cancer.
Radio Isotope
A radioisotope (radioactive isotope) is an atom with an unstable nucleus that emits radiation as it decays into a more stable form. These isotopes can release alpha, beta, or gamma radiation.
- Examples of Radioisotopes and Their Uses:
Carbon-14 – Used in carbon dating to determine the age of ancient objects.Iodine-131 – Used in medical treatments for thyroid disorders. Uranium-235 – Used as fuel in nuclear power plants.
Radioactive
emitting or relating to the emission of ionizing radiation or particles.
Half Life
half-life, in radioactivity, the interval of time required for one-half of the atomic nuclei of a radioactive sample to decay (change spontaneously into other nuclear species by emitting particles and energy), or, equivalently, the time interval required for the number of disintegrations per second of a radioactive material to decrease by one-half.
Applications of Alpha Radiation
Smoke detectors – Americium-241 ionises air to detect smoke.
Spacecraft power – Used in RTGs to generate electricity.
Cancer treatment – Alpha therapy targets and kills cancer cells.
Applications of Beta Radiation
Medical tracers – Used in PET scans to diagnose diseases.
Thickness control – Measures paper and metal thickness.
Radiotherapy – Treats certain cancers by destroying cells.
Carbon Dating:- The beta decay of carbon-14 (C-14) to nitrogen-14 (N-14) is used to determine the age of organic materials, such as artifacts, wood, and animal remains.
Applications of Gamma Radiation
Cancer treatment – Kills cancer cells in radiotherapy.
Sterilising medical equipment – Eliminates bacteria for safety.
Food irradiation – Preserves food by killing bacteria and pests.
Ionising Radiation
Alpha, Beta, and GAmma radiation are all typs of ionising radiation. They cause the removal of electrons which result in the formation of positive ions.
X + radiation → (X+) + (e-)
Detecting Radiation
A Geiger-Muller tube detects radiation by ionising gas within the tube, creating a current pulse that’s amplified and counted, indicating the presence and intensity of radiation
Bacquerel
A becquerel (Bq) is the SI unit of radioactivity, representing one radioactive decay per second.
Ionising Radiation exmaples
onizing Radiation (High energy, can remove electrons from atoms)
- Alpha (α) Radiation – Heavy, positively charged particles; low penetration (stopped by paper or skin).
- Beta (β) Radiation – Fast-moving electrons; medium penetration (stopped by plastic or aluminum).
- Gamma (γ) Radiation – High-energy electromagnetic waves; highly penetrating (requires lead or concrete to stop).
- Neutron Radiation – Neutral particles that penetrate deeply; found in nuclear reactors and explosions.
Sievert
The sievert quantifies the amount of radiation exposure that could cause a certain level of biological damage, such as the risk of radiation-induced cancer or genetic damage.
Effects of Ionising Radiation
Can cause:
→ Burns,
→ Destruction of cells,
→ and cancer
due to mutation of DNA. This can be used to kill microorganisms so that the objects are sterilised
Non-Ionizing Radiation examples
Non-Ionizing Radiation (Low energy, does not ionize atoms)
- Radio Waves – Used in communication (radio, TV, Wi-Fi).
- Microwaves – Used in cooking and mobile phones.
- Infrared Radiation – Used in remote controls and thermal imaging.
- Visible Light – The only type of radiation we can see.
- Ultraviolet (UV) Radiation – Causes sunburn and is used in sterilization.
Nuclear Fission
Nuclear fission is the process where a large atomic nucleus, such as uranium-235 or plutonium-239, splits into two smaller nuclei. This process releases a large amount of energy, along with extra neutrons that can trigger more fission reactions in a chain reaction. Fission is used in nuclear power plants to generate electricity and in atomic bombs for explosive energy.
