Particles And Waves Flashcards
Standard model
Understanding of the fundamental nature of matter
What are the two fundamental matter particle groups
Leptons and Quarks
Six leptons
Electron, muon, tau, electron neutrino, muon neutrino, tau neutrino
Six quarks
Up, down, strange, charm, top, bottom
What is Antimatter
Every fundamental particle has an equivalent antimatter. Same mass but opposite charge
What do quarks combine to form
Hadrons
Mesons are formed..
When two quarks combine
Baryons are formed…
When three quarks combine
Four fundamental forces
Gravitational forces
Electromagnetic forces
Weak nuclear forces
Strong nuclear forces
Force mediating particle for gravitational force
Graviton
Force mediating particle for electromagnetic force
Photon
Force mediating particle for weak nuclear charge
W and Z Bosons
Weak nuclear forces are associated with…
Beta decay
Force mediating particle for strong nuclear force
Gluon
What does the strong nuclear forces do?
Holds quarks together to form particles such as protons and neutrons
A magnetic field is a ….
Region of space around a pole where another pole will experience a force
What can determine the direction of a force
Flemings right hand rule
Flemings right hand rule
First finger- field
Second finger- current
Thumb- thrust
What happens in particle accelerators
Charged particles are accelerated by electric fields and magnetic fields are used to change their path.
Isotopes are…
Atoms of the same element that have different number of neutrons in the nucleus
3 types of nuclear radiation
Alpha
Beta
Gamma
Alpha decay
-4
Br
-2
Beta decay
0
Br
-1
Gamma decay
0
Br + gamma ray
0
What happens in a fusion reaction
Small nuclei are joined together
What happens in a fission reaction
Large nucleus is split into smaller nuclei
2 types of fission reactions
Spontaneous- randomly
Induced- forced, bombarded by a neutron
Explain a nuclear fusion reaction (long)
It requires extremely high temperatures to create the plasma in which the reactions take place. This poses difficulties to find a suitable coolant, to extract useful energy from the reaction, and containment, to prevent the high temperatures from melting the container the plasma is in.
What is the photoelectric effect evidence of
Light behaving like a particle
What is the work function
The minimum amount of energy required for photoemission to occur
What is the threshold frequency
The minimum frequency of light that causes photoemmision to occur
Wave particle duality is our understanding …
That photons exhibit both wave and particle properties
Coherent waves have…
The same:
Velocity
Wavelength
Frequency
Constructive interference
Waves meet in phase
Destructive interference
Waves arrive out of phase
Interference patterns can occur when:
-Waves are produced by two separate coherent sources
-waves from a single source pass through a double slit
- a direct wave from a source interferes with a reflected wave from a nearby surface
What is refraction?
It’s the change in the speed of light as it travels from one medium to another.
How is a spectrum produced from a prism?
The refractive index of a material changes slightly with frequency.
What happens at small angles of incidence?
Most of the light is refracted away from the normal, but some light is reflected back known as partial internal reflection
What is the critical angle
When the angle of refraction is equal to 90’.
What is total internal reflection?
Angles above the critical angle, all the light is reflected inside the medium
An electron moves to a higher energy level…
When it absorbs the energy of a photon
When an electron moves from a higher to lower energy level…
A photon is emitted
Continuous spectra are produced…
When energy is supplied to solids, liquids and high pressure gases.
Line emission spectra are produced…
When energy is supplied to low pressure gases. Line emissions correspond to the frequencies of the photons emitted when the electron moves down the energy levels
Absorption spectra are formed…
When light with a continuous spectrum passes through a low pressure gas. The lines are formed when electrons in the gas absorb photons to move up an energy level.
What type of particle is made of a quark/antiquarks pair?
Mesons
State what it meant by the term critical angle
The angle of incidence such that the angle of refraction of 90’
State two features of the Bohr model of the atom
-Positively charged nucleus
-discrete electron energy levels
What is the equivalent unit of farads
Coulombs per volt
Describe how the apparatus could be used to verify the inverse square law for a point source of light
Obtain values of irradiance for different distances
Plot graph of I against 1/d2
Straight line through the origin verifies the inverse square law
Describe how a student would use apparatus to determine the internal resistance of the cell
Adjust the variable resistor and take readings of V and I.
Plot a graph of V against I.
Gradient of graph= -r
