Particles Flashcards
What are isotopes
Atoms with the same number of protons but different number of neutrons
What is the specific charge of a particle
The ratio of its charge to its mass
Equation of specific charge
SC = Q/M
Ckg-1 = C/kg
What is the strong force responsible for, its range and exchange particle
Responsible for keeping the nucleus together. Range = 1x10^-18 metres
Gluon
What are released in alpha decay
2 neutrons and 2 protons
Describe beta decay
A neutron decays into a proton and electron - the electron is emitted
What are photons
A “packet”/“quantum” of electromagnetic energy
Define annihilation
A particle and its antiparticle collide producing two photons
The total energy of the photons = the combined rest mass and Ek of the particle and antiparticle
Define pair production
A photon turns into a particle and its antiparticle. The minimum photon energy = twice the rest mass of the particle produced
Name the 4 fundamental forces
Gravity, Electromagnetic, Weak force and Strong force
What are the gravity, electromagnetic and weak force range
infinite, infinite, 1x10^-18 metres
What is the gravity force responsible for and its exchange particle
The attractive force between any two masses
Graviton
What is the electromagnetic force responsible for and its exchange particle
Attractive or repulsive between any two charges
Virtual photon
What is the weak force responsible for and its exchange particle
Beta decay
W+/W-
What is an antiparticle
A particle with the same mass and rest energy but opposing charge
What is the difference between hadrons and bosons?
Bosons are fundamental force exchange particles
What is the difference between baryons and mesons?
Baryons contain qqq, mesons contain qq
What fundamental forces can leptons experience?
Gravity, electromagnetic and weak
What is the only stable baryon
proton
In which interaction is strangeness NOT conserved?
Weak
Quark construct of a proton and a neutron
p = uud
n = udd
Quark construct of a pion
π^+ = up and anti-down
π^0 = up and anti-up
quark construct of a kaon
k+ = up and anti-strange
k^0 = down anti-strange
How does light behave as a particle
Photoelectric effect
What is one electron-volt equivalent to in J
1eV = 1.6X10^-19 J
What is the ground state
Nearest possible position to the nucleus
What are excited states
Energy levels above the ground state but below the ionisation level
How can you increase the maximum kinetic energy of a photoelectron
Increase the frequency of the incoming photon/decrease the wavelength
Why might electrons not be emitted from a plate
The energy is less than the work function
What is the work function
The minimum energy needed to release an electron from the surface of a metal
What is ionisation
the energy required to remove one electron from an atom
What can cause ionisation/excitation
- collision of photons or electrons
- nuclear radiation
- heating
- passing an electric current through a gas
What is excitation
When an electron moves from a lower to a higher energy level within an atom
Evidence of light behaving as a wave
Diffraction
Evidence for an electron behaving as a particle
deflection in a field
Evidence for an electron behaving as a wave
diffraction
(particles can’t be deflected so electron must be waves)
In β– decay what decays
n ===> p + e- + anti-electron neutrino
In β+ what happens
p ===> n + e+ + electron neutrino
