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?
Number of complete waves passing a point per second
What is the wavelength of a wave?
Distance between 2 adjacent crests of a wave
What are the 7 types of electromagnetic radiation?
Radio waves
Microwaves
Infra-red
Visible light
Ultra-violet
X-rays
Gamma rays
Which EM wave has the highest frequency?
Radio
What EM radiation has the highest wavelength?
Gamma
What does the higher the frequency mean in terms of energy?
Greater the energy
What are photons?
Packets of EM radiation
What is the formula for the energy of a photon?
E=hf
What does h stand for in E=hf?
What are the units?
Planck’s constant
Js
What is f in E=hf?
What are the units?
Frequency of light
Hz
What is the equation that relates frequency, wavelength and speed of light?
Frequency = speed of light ÷ wavelength
What is an antiparticle?
Each particle has a corresponding antiparticle with the same mass and rest energy but with opposite charge
What are all particles known as?
Matter
What are antiparticles known as?
Antimatter
What is pair production?
When energy is converted into mass, you get equal amounts of matter and antimatter
When does pair production happen?
When there is enough energy to produce the masses of the particles
What must pair production always produce?
Why?
A particle and its corresponding antiparticle
Because certain quantities must be conserved
Why do the particles in a detector curve away from each other in opposite directions?
Because they are in an applied magnetic field and have opposite charges
What is the minimum energy needed for pair production?
Total rest energy of the particles produced
What is the rest energy of a particle?
Amount of energy that would be produced if all of its mass was transformed into energy
Why is the minimum energy needed for pair production 2E0?
Pair production always produces a particle-antiparticle pair, which both have a rest energy of E0
So for there to be enough energy to produce the particles, it must be 2E0
What is annihilation?
When a particle meets its antiparticle
What happens to the mass of the particle and antiparticle during annihilation?
Gets converted back to energy in the form of 2 gamma ray photons
What does annihilation produce?
2 photons
