Section 2 - Particles and Quantum Phenomena Flashcards
What are the constituents of an atom?
Protons and Neutrons (in the nucleus)
Electrons orbiting.
What is an isotope?
Same proton number, different nucleon number.
What is the atomic number?
Number of protons
What is the mass number?
Number of protons and neutrons
What is specific charge?
Charge(Q) / Mass(kg)
What are the 4 fundamental forces?
Electromagnetic, Gravity, Strong Nuclear Force, Weak Force
What is the range of the Strong Nuclear Force?
Repulsive : 0-0.5 fm
Attractive : 0.5 - 4 fm
What is the range of a gravitational field?
Infinite
What is the range for an electromagnetic force?
Infinite
Rank the 4 fundamental forces in terms of strength. Strongest to Weakest
- Strong Nuclear Force
- Electromagnetic
3.Weak Force
4.Gravity
What does the SNF affect?
Hadrons
What does gravity affect?
Masses
What does the weak force affect?
Leptons and Hadrons
What does the Electromagnetic force affect?
Charges
True or False the SNF does not conserve strangeness?
False
True or False the Weak Force does not conserve strangeness?
True
Force carrier for the SNF?
Pion+ , Pion0 , Pion-
Force carrier for the weak force?
W+,W0,W-
Force carrier for EM?
Virtual photon
Range of a virtual photon?
Infinite
How heavy is a W boson?
Heavier than a copper nucleus
Does a W boson have a short range or a long range?
Short range
Equation for power of a laser?
n.h.f
What are anti-particles?
Particles that have the same charge ,mass and will annihilate when it collides with its matter particle.
What is rest energy?
The energy due to rest mass
What is the process of converting mass to energy called?
Annihilation
What is the process of converting energy to mass?
Pair production
What is annihilation?
A particle and an anti-particle collide.
They produce two photons.
Travelling in opposite directions.
To conserve momentum.
What is pair production?
A single photon produces a particle and an anti-particle pair.
Draw the feynmann diagram for electron repulsion
Check Notes
Draw the feynmann diagram for proton repulsion
Check Notes
Draw the feynmann diagram for electron capture
Check Notes
Draw the feynmann diagram for neutron-neutrino
Check Notes
Draw the feynmann diagram for proton- anti-neutrino
Check Notes
Draw the feynmann diagram for Beta+ decay
Check Notes
Draw the feynmann diagram for Beta- decay
Check Notes
What are leptons?
Fundamental Particle
Examples of leptons
Muon, electron,positron
What are Hadrons
Particle made up of quarks
What are the two types of Hadrons?
Meson, Baryon
How many Quarks does a baryon have?
3
How many quarks does a meson have?
2: 1 quark, 1 anti-quark
What is the most stable baryon?
Proton
What quarks is a pion+ made up of ?
up , anti-down
What quarks is a pion- made up of ?
down, anti-up
What quarks is a pion0 made up of ?
up, anti-up or down, anti-down or strange, anti-strange
What quarks is a Kaon+ made up of ?
up , anti-strange
What quarks is a Kaon- made up of ?
anti-up, strange
What quarks is a Kaon0 made up of ?
anti-down, strange
List types of Kaon decay.
K -> pi
K -> mu + anti-neutrino
K -> anti-mu + neutrino
List types of Pion decay.
K -> mu + anti-neutrino
K -> anti-mu + neutrino
Equation for decay of a Muon
electron + anti-neutrino(e) + neutrino(mu)
What are the values that are conserved?
Charge
Baryon Number
Strangeness (only in strong interaction)
lepton number
Energy
Momentum
Lepton flavour
What does the photoelectric effect prove?
It proves that light can act like a particle.
What is stopping potential?
The minimum pd required to stop photo-electric emission
What is a conduction electron?
A free electron in a metal that isn’t moving
What is excitation?
When an electron moves up an energy level
What is an ion?
A charged particle
Two ways that an ion is formed?
Collisions with electrons
Collisions with photons
Are energy levels discrete or continuous?
Discrete
Explain excitation by electron collision.
1 to 1 collision with an electron. Its energy must be greater than the energy level to excite.
Explain excitation by photon absorption.
1 to 1 interaction with a photon. Photon energy must be the exact energy need to excite to an energy level. As photon can not be partially absorbed.
Explain the process of fluorescence.
- Mercury gas is trapped in the tube.
- A pd is applied across the tube.
- This causes a flow of electrons to floe through the tube.
- Electrons collide with the mercury atoms.
- Mercury atoms excite and the de-excite to release uv photons
- UV photons then absorbed by the phosphorus coating of the tube.
- Coating excites then de-excites realeasing photons of multiple wavelengths (White light).
What does a line emission spectra show?
It shows the wavelengths of photons released from de-exciting electrons.
What does a line absorption spectra show?
Continuous spectra of dark lines that represents wavelengths that are absorbed.
Proof that electrons have wave like properties
Electron diffraction
Proof that electrons have particle like properties
Photoelectric effect
What is the De Broile wavelength?
Lambda is proportional to 1/momentum.
anything with mass has a wavelength.
What is the lowest energy level called?
Ground state
What is the highest energy level called?
Ionisation state
How does a dishcarge tube work?
- High pd accross tube accelerates electrons
- Electrons now have high KE and atoms hydrogen atoms inside can absorb the electron energy and excite to a higer energy level
- de-exitation transitions can then relsease photons with energy that correspond to the size of the energy gap
Why are energy levels negative?
To become free/to remove an electron (reach zero energy)
energy has to be supplied
