1.3 Antiparticles and Photons Flashcards
What is the electromagnetic spectrum?
A continuous spectrum of all the possible frequencies of electromagnetic radiation
What is the frequency of a wave?
The number of complete waves passing a point per second
What is the wavelength of a wave?
The distance between two adjacent crests of a wave
What are the types of electromagnetic radiation in order of increasing frequency?
- radio waves
- microwaves
- infrared
- visible light
- ultraviolet
- x-rays
- gamma rays
What are photons?
Packets of electromagnetic waves
What is the equation for energy of a photon?
Energy of one photon = Plancks constant x frequency of light
How are frequency, wavelength and speed of light related?
Frequency = speed of light / wavelength
What is an antiparticle?
Each particle has a corresponding antiparticle with the same mass and rest energy but opposite charge
What are all particles known as?
Matter, and all antiparticles are known as antimatter
What is the relative charge of a proton and antiproton?
+1 for proton
-1 for antiproton
What are the relative charges of a neutron and an antineutron?
Both zero
What are the relative charges of an electron and a positron?
- electron is -1
- positron is +1
What are the relative charges of a neutrino and an antineutrino?
Both zero
What is pair production?
When energy is converted into mass, giving you equal amounts of matter and antimatter
When does pair production happen?
If there is enough energy to produce the masses of the particles
What does pair production produce?
It must always produce a particle and its corresponding antiparticle
What happens when two protons collide at high speed?
The two protons collide and produce a proton-antiproton pair
What can be produced in pair production?
- a proton antiproton pair
- an electron-positron pair if the photon has enough energy
What is the minimum energy needed for pair production?
The total rest energy of the particles that are produced
What is the rest energy of a particle?
The amount of energy that would be produced if all of a particles mass was transferred into energy
What is the minimum energy needed for pair production equal to?
Emin = 2E0
Minimum energy needed = 2 x rest energy of particle type produced
What happens when a particle meets its antiparticle?
Annihilation - all of the mass of the particle and antiparticle gets converted back to energy in the form of two gamma ray photons.
How do you calculate the minimum energy of a photon produced by annihilation?
Minimum energy of photon produced = rest energy of particle type annihilated (in MeV)
Emin = E0
