physics- Alpha particles Flashcards
What is radioactive decay?
The process by which an unstable nucleus emits particles or radiation to become more stable.
What are the three main types of radioactive particles or radiation?
- Alpha particles
- Beta particles
- Gamma radiation
Define an alpha particle.
A high-energy helium nucleus containing 2 protons and 2 neutrons, with a mass of 4u and a charge of +2e.
What happens to a nucleus when an alpha particle is emitted?
- Loses 2 protons
- Loses 4 nucleons
- Proton number decreases by 2
- Nucleon number decreases by 4
What is a beta-minus particle?
A high-energy electron with a mass of 0.0005u and a charge of -1e.
What occurs during beta-minus decay?
A neutron turns into a proton and emits an electron and an anti-electron neutrino.
What is a beta-plus particle?
A high-energy positron, the antimatter particle of the electron, with a mass of 0.0005u and a charge of +1e.
What occurs during beta-plus decay?
A proton turns into a neutron and emits a positron and an electron neutrino.
Define gamma radiation.
A type of high-energy electromagnetic radiation emitted by nuclei that need to lose energy.
What is the nuclear notation for gamma radiation?
Gamma radiation is represented as γ.
What is the effect of alpha decay on the parent nucleus?
The parent nucleus transforms into a daughter nucleus with a decreased proton and nucleon number.
What is the ionising ability of radiation?
A measure of the amount of ionisation caused when nuclear radiation passes through a material.
How does penetrating power relate to ionising ability?
The greater the ionising ability, the lower its penetrating power, and vice versa.
What can happen if radiation collides with an atom?
It can knock out electrons, ionising the atom and causing chemical changes.
How can alpha particles be stopped?
By a single sheet of paper.
How can beta particles be stopped?
By a few millimeters of aluminium foil.
How can gamma radiation be reduced?
By several meters of concrete or several centimeters of lead.
What happens to charged particles in an electric field?
They undergo deflection.
How do alpha and beta particles behave in a magnetic field?
- Alpha particles are deflected towards the negative plate
- Beta particles are deflected towards the positive plate
- Gamma radiation is not deflected
What is the range of alpha particles in air?
Around 3-7 cm.
What is the range of beta particles in air?
Around 20 cm - 3 m, depending on their energy.
What defines the properties of gamma radiation?
It is the least ionising type of radiation and has the most penetrating power.
What is a common mistake regarding alpha decay?
Confusing the number of neutrons with the nucleon number.
Fill in the blank: Alpha particles have the highest _______ due to their charge of +2e.
ionising ability
Fill in the blank: Beta particles are a _______ ionising type of radiation.
moderately
Fill in the blank: Gamma rays are not deflected in _______ and _______ fields.
electric; magnetic
True or False: Alpha particles can travel the furthest in air before being absorbed.
False
What happens to the nucleon number during beta-plus decay?
It remains the same.
