π©» β’ Lesson 3.8 : Nuclear Physics (Phys) Flashcards
After this deck, you will know all about the compositions; nucleus, protons, and neutrons, followed by radioactivity, decay, half-life, as well as the applications and safety precautions of nuclear physics.
What is the composition of the nucleus?
The nucleus is composed of protons (positive charge) and neutrons (neutral charge).
What is the relationship between proton number and charge on a nucleus?
The proton number (atomic number) gives the charge on the nucleus, as each proton has a charge of +1.
What are the relative charges of protons, neutrons, and electrons?
Protons: +1
Neutrons: 0
Electrons: -1
What is nuclear fission?
Splitting of a nucleus into smaller parts.
What is nuclear fusion?
Joining of two smaller nuclei to form a larger one.
What are proton number (Z) and nucleon number (A)?
β’ Proton number (Z): Number of protons in the nucleus (atomic number).
β’ Nucleon number (A): Total number of protons and neutrons.
To calculate neutrons: Neutrons = A - Z.
What is nuclide notation?
Nuclide notation is written as A_Z X,
Where A is the mass number, Z is the atomic number, and X is the element.
What is an isotope?
Isotopes are different forms of the same element with the same number of protons but different numbers of neutrons.
Some isotopes are radioactive.
What is ionising nuclear radiation?
Ionising nuclear radiation is radiation that can remove electrons from atoms, creating ions.
What is background radiation?
It comes from natural sources, like:
β Radon gas (in the air)
β Rocks and buildings
β Food and drink
β Cosmic rays
How can ionising radiation be measured?
Ionising radiation can be measured using a detector connected to a counter, and the count rate is measured in counts per second or counts per minute.
What are the characteristics of alpha (Ξ±) emission?
Nature: Helium nucleus
Ionising effect: High
Penetrating ability: Low (stopped by paper or skin)
What are the characteristics of beta (Ξ²) emission?
Nature: Electron
Ionising effect: Moderate
Penetrating ability: Moderate (can pass through paper but stopped by a few mm of aluminium)
What are the characteristics of gamma (Ξ³) emission?
Nature: High-energy electromagnetic wave
Ionising effect: Low
Penetrating ability: High (can pass through several cm of lead or meters of concrete)
What is radioactive decay?
A change in an unstable nucleus that results in the emission of Ξ±, Ξ², and/or Ξ³ radiation.
Itβs spontaneous and random.
What happens during Ξ²-emission?
A neutron turns into a proton and an electron (Ξ²-particle).
What is the half-life of an isotope?
The time it takes for half the nuclei of an isotope in any sample to decay.
How do you calculate the remaining amount of an isotope after a certain time?
Use the half-life to find how many half-lives have passed and divide the initial amount by 2 for each half-life.
How is radioactivity used in household fire alarms?
Smoke alarms use alpha radiation to ionize air, allowing the detection of smoke particles that interrupt the ionized current.
How is radioactivity used in food preservation?
Gamma rays are used to irradiate food, killing bacteria and pests to increase shelf life and safety.
How are gamma rays used for sterilisation?
Gamma rays are used to sterilize medical equipment by killing bacteria and viruses without damaging the equipment.
How is radioactivity used to measure material thickness?
Gamma or beta radiation is used to measure and control the thickness of materials, with radiation choice based on penetration and absorption properties.
How are gamma rays used in cancer treatment?
Gamma rays are used to diagnose and treat cancer by targeting and destroying cancerous cells.
What are the effects of ionising radiation on living organisms?
Ionising radiation can cause cell death, mutations, and cancer due to DNA damage.
How are radioactive materials safely handled?
Radioactive materials are safely handled by reducing exposure through time, distance, and shielding with materials like lead or concrete.
