Antiparticles And Photons Flashcards
What is the electromagnetic spectrum?
A continuous spectrum of all the possible frequencies of electromagnetic radiation.
What type of light is electromagnetic radiation?
Visible light.
Define “frequency”.
The number of complete waves passing a point per second.
Define “wavelength”.
The distance between two adjacent crests of a wave.
What are photons?
Photons are “wave-packets” that EM waves exist in.
What is the equation used to calculate the energy carried by one photon?
Energy of one photon = plancks constant x frequency of light
What is the equation that relates frequency, wavelength and speed of light?
Frequency = (speed of light)/wavelength
What are the units of the following: A) energy B) frequency C) Planck's constant D) speed of light E) wavelength
A) joules B) hertz C) Joules seconds D) metres per second E) metres
State the relative charge of a proton and it’s antiparticle?
Proton: +1
Antiproton: -1
State the relative charge of a neutron and it’s antiparticle.
Neutron: 0
Antineutron: 0
State the relative charge of an electron and it’s antiparticle.
Electron: -1
Positron: +1
State the relative charge of an electron neutrino and it’s antiparticle.
Electron neutrino: 0
Electron anti-neutrino: 0
What is pair production?
A process of converting energy to mass in which a gamma ray photon has enough energy to produce a particle-antiparticle pair.
Why must pair production always produce a particle AND it’s corresponding anti-particle?
Certain quantities must be conserved.
What equation is used to calculate the minimum energy needed for pair production?
Minimum energy = 2 x rest energy of particle type
What is annihilation?
Annihilation is the result of a particle meeting it’s antiparticle.
What is the result of annihilation?
All the mass of the particle and antiparticle gets converted back to energy in the form of two gamma ray photons.
Why do antiparticles not exist in ordinary matter?
They can only exist for a fraction of a second before annihilation.
What equation is used to calculate the minimum energy of a photon produced by annihilation?
Minimum energy = rest energy of particle type annihilated
