Particle Physics and Quantum Phenomena Flashcards

Flashcards covering key concepts from the lecture notes on particles, antiparticles, quantum phenomena, and related topics.

What three constituents form an atom?

Protons, neutrons, and electrons

What particles are found in the nucleus of an atom?

Protons and neutrons

What is the specific charge of a particle?

The charge-to-mass ratio, calculated by dividing a particle's charge by its mass.

What is the proton number (Z)?

The number of protons in an atom.

What is the nucleon number (A)?

The number of protons and neutrons in an atom.

What are isotopes?

Atoms with the same number of protons but different numbers of neutrons.

What is carbon-14 used for?

To find the approximate age of an object containing organic material through carbon dating.

What force keeps nuclei stable?

The strong nuclear force (SNF)

What does the strong nuclear force counteract?

The electrostatic force of repulsion between protons in the nucleus.

Where does alpha decay occur?

In large nuclei with too many protons and neutrons.

What happens to the proton number during alpha decay?

It decreases by 2.

What happens to the nucleon number during alpha decay?

It decreases by 4.

Where does beta-minus decay occur?

In neutron-rich nuclei.

What happens to the proton number during beta-minus decay?

It increases by 1.

What happens to the nucleon number during beta-minus decay?

It stays the same.

What is the purpose of hypothesizing Neutrinos during beta-minus decay?

To account for the missing energy, as observations of the energy levels of the particles before and after the decay showed that energy was not conserved

What is an antiparticle?

A particle with the same rest energy and mass as its corresponding particle, but with opposite properties (e.g., charge).

What is annihilation?

The collision of a particle and its corresponding antiparticle, resulting in the conversion of their masses into energy (photons).

What is pair production?

The conversion of a photon into an equal amount of matter and antimatter.

Name the four fundamental forces.

Gravity, electromagnetic, weak nuclear, and strong nuclear.

How do exchange particles cause forces between particles?

By carrying energy and momentum between the particles experiencing the force.

What fundamental force is responsible for beta decay?

The weak nuclear force.

What interaction are electron capture and electron-proton collision examples of?

Weak Interaction

What is the difference between hadrons and leptons?

Leptons are fundamental particles that do not experience the strong nuclear force, while hadrons are formed of quarks and experience the strong nuclear force.

What are the three types of hadrons?

Baryons, antibaryons, and mesons.

What is the structure of Baryons?

Formed of 3 quarks.

What is the structure of Antibaryons?

Formed of 3 antiquarks.

What is the structure of mesons?

Formed of a quark and an antiquark.

What does the baryon number of a particle indicate?

Whether it is a baryon (1), antibaryon (-1), or not a baryon (0).

Which of the properties need to be conserved during a particle interaction?

Charge, Baryon number, Electron lepton number, Muon lepton number

What is a strange particle?

A particle produced by the strong nuclear interaction but decays by the weak interaction.

What is the role of Kaons?

Strange particles, which decay into pions, through the weak interaction.

What is the law of conservation of strangeness?

Strange particles must be created in pairs, as strangeness must be conserved in strong interactions. However, in weak interactions strangeness can change by 0, +1 or -1.

What is the role of the scientific community in interpreting the experimental evidence?

These pieces of experimental evidence must first be published to allow them to be peer-reviewed by the community to become validated, and eventually accepted.

What is the up quark's charge?

+2/3 e

What is the down quark's charge?

-1/3 e

What is the strange quark's charge?

-1/3 e

What is special about Beta-minus and beta-plus decay?

They are both caused by the weak interaction because there is a change of quark type.

What is the photoelectric effect?

The emission of photoelectrons from the surface of a metal after light above a certain frequency is shone on it.

What is the threshold frequency?

The minimum frequency of light required to cause photoelectric emission from a metal surface.

What does the photon model of light suggest?

EM waves travel in discrete packets called photons, which have an energy which is directly proportional to frequency; Each electron can absorb a single photon, therefore a photoelectron is only emitted if the frequency is above the threshold frequency; If the intensity of the light is increased, if the frequency is above the threshold, more photoelectrons are emitted per second.

What is the work function of a metal?

The minimum energy required for electrons to be emitted from the surface of a metal.

What is the stopping potential?

The potential difference required to stop the photoelectrons with the maximum kinetic energy.

How can electrons gain energy from collisions with free electrons?

Move up in energy level (excitation) or be removed from the atom entirely (ionization).

What happens when an electron returns to its ground state after excitation?

It releases the energy it gained in the form of a photon.

Give an example of a practical use of excitation?

Fluorescent tube in order to produce light

What is one electron volt (eV)?

The energy gained by one electron when passing through a potential difference of 1 volt.

What do the lines in a line spectrum represent?

Different wavelengths of light emitted by the tube.

What is a line absorption spectrum?

A continuous spectrum with black lines at certain wavelengths, representing the energy differences between energy levels.

Give an example of light acting as a wave?

Diffraction and interference

Give an example of light acting as a particle?

The photoelectric effect

What is De Broglie's hypothesis?

If light has particle properties, then particles should also have wave-like properties.