"Half-life (symbol t½) is the time required for a quantity (of substance) to reduce to half of its initial value."
The time it takes for half of a radioactive substance to decay.
Radioactivity: The phenomenon of atoms emitting energy in the form of particles or radiation.
Types of radiation: Alpha, beta, and gamma radiation, which differ in their properties.
Half-life: The time it takes for half of the original radioactive substance to decay.
Decay constant: A measure of the rate at which a radioactive substance decays.
Radioactive decay series: A sequence of decays in which an atom goes through multiple transformations to reach a stable state.
Activity: The rate at which a sample of radioactive material undergoes radioactive decay.
Radiation exposure: The amount of ionizing radiation absorbed by a person or object.
Radiation shielding: Ways to prevent or reduce exposure to ionizing radiation.
Radiation safety: Guidelines and procedures for handling and working with radioactive materials.
Nuclear reactions: Processes that involve changes in the nucleus of an atom, often resulting in the release of energy and radiation.
Radioisotope production: Methods for creating radioactive isotopes for various applications in medicine, industry, and research.
Environmental radiation: Sources and effects of natural and man-made radiation in the environment.
Radiation biology: The study of the effects of ionizing radiation on living organisms.
Radiation therapy: The medical use of ionizing radiation to treat cancer and other diseases.
Nuclear power: The generation of electricity through controlled nuclear reactions.
Alpha radiation: An alpha particle is made up of two protons and two neutrons, and has a charge of +2. It is the heaviest and slowest type of radiation, and is stopped easily by a sheet of paper or the outer layer of skin. However, if alpha particles are inhaled or ingested, they can cause significant damage to internal organs.
Beta radiation: A beta particle is essentially an electron that is ejected from the nucleus of an atom during decay. Beta particles have a charge of either -1 or +1, and are faster and more penetrating than alpha particles. They can be stopped by a layer of clothing or a thin sheet of metal.
Gamma radiation: Gamma rays are high-energy photons emitted during decay, and they are the most penetrating type of radiation. They have no mass or charge, and can only be stopped by thick layers of concrete or lead. Gamma radiation can cause a variety of health problems, including radiation sickness and an increased risk of cancer.
Neutron radiation: This type of radiation is emitted during nuclear fission and fusion reactions, and consists of high-energy neutrons. Neutron radiation can be very damaging to living tissue, and requires specialized shielding to protect against.
Positron radiation: A positron is an antiparticle of the electron, with a charge of +1. When a positron and an electron come into contact, they annihilate each other, releasing gamma rays in the process. Positron radiation is used in medical imaging techniques like PET scans.
X-rays: X-rays are a type of electromagnetic radiation produced by high-energy electrons colliding with matter. They are used in medical imaging and some types of cancer treatment, but can also cause health problems if not used correctly.
Cosmic radiation: Cosmic radiation is a type of high-energy radiation that comes from sources beyond the Earth's atmosphere, such as the sun and other stars. It can be dangerous to astronauts and airplane pilots who are exposed to high levels of cosmic radiation on long flights.
"The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable atoms survive."
"For example, the medical sciences refer to the biological half-life of drugs and other chemicals in the human body."
"Half-life is constant over the lifetime of an exponentially decaying quantity, and it is a characteristic unit for the exponential decay equation."
"The original term, half-life period, dating to Ernest Rutherford's discovery of the principle in 1907..."
"Rutherford applied the principle of a radioactive element's half-life in studies of age determination of rocks by measuring the decay period of radium to lead-206."
"The converse of half-life (in exponential growth) is doubling time."
"The original term, half-life period, dating to Ernest Rutherford's discovery... was shortened to half-life in the early 1950s."
"The term is also used more generally to characterize any type of exponential (or, rarely, non-exponential) decay."
"The accompanying table shows the reduction of a quantity as a function of the number of half-lives elapsed."
"Half-life is constant over the lifetime of an exponentially decaying quantity..."
"The term is also used more generally to characterize any type of exponential (or, rarely, non-exponential) decay."
"Half-life (symbol t½)..."
"The time required for a quantity (of substance) to reduce to half of its initial value."
"The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable atoms survive."
"Half-life (symbol t½) is the time required for a quantity (of substance) to reduce to half of its initial value."
"For example, the medical sciences refer to the biological half-life of drugs and other chemicals in the human body."
"Rutherford applied the principle of a radioactive element's half-life in studies of age determination of rocks by measuring the decay period of radium to lead-206."
"Half-life is constant over the lifetime of an exponentially decaying quantity, and it is a characteristic unit for the exponential decay equation."
"The accompanying table shows the reduction of a quantity as a function of the number of half-lives elapsed."