PARTICLES Flashcards
(25 cards)
What do A and Z represent in the notation AZ X?
A = mass number (protons + neutrons), Z = number of protons
What are isotopes?
Isotopes are atoms with the same number of protons but different number of neutrons.
How is specific charge calculated?
Specific charge = charge / mass
Example: A Hydrogen atom (1H) nucleus has a charge of 1.60 x 10-19 C and a mass of 1.67 x 10-27 kg, so its specific charge is 9.58 x 107 Ckg-1.
What is the strong nuclear force?
The strong nuclear force overcomes the electrostatic force of repulsion between protons in the nucleus and keeps the protons and neutrons together.
What is the range of the strong nuclear force?
The range is 3-4 femtometres (fm).
What is alpha radiation?
Alpha radiation (α) consists of alpha particles with two protons and two neutrons, symbolized as 24α.
What is the equation for alpha decay?
AX → A−4Y + 4α Z Z−2
What is beta radiation?
Beta radiation (β) consists of fast-moving electrons, symbolized as 0 β or β− −1.
What occurs during beta decay?
A β− particle is released as a result of a neutron changing into a proton, and an antineutrino is emitted.
What is the equation for beta decay?
AZ X → AZ + 1 Y + 0− 1 β + V e
What is gamma radiation?
Gamma radiation (γ) is electromagnetic radiation emitted by an unstable nucleus, having no mass and no charge.
What is pair-production?
Pair-production is where a gamma ray photon produces a particle and its matching antiparticle.
What is the minimum energy for pair-production?
The minimum energy for a photon to undergo pair-production is the total rest energy of the particles produced.
What occurs during annihilation?
Annihilation occurs when a particle and matching antiparticle meet, converting their mass back to energy.
What is the electromagnetic force?
The electromagnetic force between two charged particles is due to the exchange of virtual photons (γ).
What is the weak nuclear force responsible for?
The weak nuclear force affects only unstable nuclei and is responsible for neutron → proton (β−) and proton → neutron (β+) decay.
What is electron capture?
In electron capture, a proton in a proton-rich nucleus turns into a neutron through weak force interaction with an inner-shell electron.
What are hadrons?
Hadrons are particles/antiparticles that interact through the strong force, such as protons and neutrons.
What are baryons?
Baryons are hadrons that consist of three quarks.
What are mesons?
Mesons are hadrons that consist of two quarks, one quark and one antiquark.
What is the charge of an up-quark?
An up-quark has a charge of +2/3.
What is the charge of a down-quark?
A down-quark has a charge of -1/3.
What happens in β- decay?
In β- decay, a down quark changes to an up quark, converting a neutron to a proton.
What happens in β+ decay?
In β+ decay, an up quark changes to a down quark, converting a proton to a neutron.
