3. Antiparticles and Photons Flashcards
What is the EM spectrum in order of increasing frequency and decreasing wavelength?
- Radio waves
- Microwaves
- Infrared radiation
- Visible light
- Ultraviolet light
- X-rays
- Gamma rays
What is the relationship between frequency and energy in EM radiation?
The higher the frequency, the greater the energy
What did Einstein name the wave packets?
Photons
How do you work out the energy of one photon?
E = hf
E is the energy of one photon in Joules
h is Planck’s constant in Js
f is the frequency of light in Hz
What is Planck’s constant?
6.63 x 10^-34 Js
What is an antiparticle?
Same mass and rest energy as its corresponding particle but oppositely-charged
What is pair production?
When energy is converted into mass you get equal amounts of matter and antimatter
When can pair production happen?
If there is enough energy to produce the masses of the particles
What must pair production always produce and why?
A particle and its corresponding antiparticle in order to conserve certain quantities like energy, momentum, baryon number etc…
Why do proton-proton collisions release a lot of energy?
Protons repel each other so a lot of energy needs to be supplied, which needs to be released
What is the equation used in pair production?
Minimum energy = 2 x rest energy
What is annihilation?
When a particle meets its antiparticle
What is the equation used in annihilation?
Minimum energy of photon produced = rest energy
How do PET (Positron Emission Tomography) scanners in hospitals work?
By putting a positron-emitting isotope in the bloodstream and detecting the gamma rays produced by the electron-positron annihilation that occurs
How is the radiation in PET scanning detected?
Using a scintillator
