Matter and Radiation - Unit 1 AQA Physics
Mindmap covering Chapter 1 - Matter and Radiation, from Nelson Thornes AQA AS Physics
- Created by: hellooooooooooooo
- Created on: 14-03-14 14:37
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- Matter and Radiation
- Inside the atom
- proton - +1.6x10^-19C... 1.67x10^-27kg
- electron -1.6x10^-19C... 9.11x10^-31kg
- neutron - 0C... 1.67x10^-27kg
- Isotopes = atoms with the same number of protons and different numbers of neutrons
- m/z ratio = specific charge
- Don't forget to multiply the mass and charge by the number of particles involved (atomic number)
- Stable and unstable nuclei
- Strong nuclear force - keeps protons and neutrons together
- attractive until 0.5fm, repulsive from here
- Alpha Decay
- Beta Decay
- Strong nuclear force - keeps protons and neutrons together
- Photons
- electromagnetic waves consist of an electric wave and a magnetic wave which travel together and vibrate...
- ...at right angles to each other and to the direction in which they are travelling
- ...in phase with each other
- packet of electromagnetic waves
- E = hf
- Power of the beam = nhf
- n = number of photons in the beam passing a fixed point each second
- f = frequency of photons
- h = plank's constant
- = c/f
- electromagnetic waves consist of an electric wave and a magnetic wave which travel together and vibrate...
- Particles and antiparticles
- particle and antiparticle...
- meet... annihilation
- a particle and corresponding antiparticle meet and their mass is converted into radiation energy
- meet...total rest mass converted to photons
- have exactly the same rest mass
- have exactly opposite charges
- meet... annihilation
- Positron emission = positron changes to neutron in anstable nucleus with too many protons
- pair production - photon with sufficient energy changes to a particle-antiparticle pair, which then separate from each other
- minimum energy of photon needed = 2E..=hf
- 1eV = the energy transferred when an electron is moved through a potential difference of 1V
- Cloud chamber - discovery of the positron
- particle and antiparticle...
- how particles interact
- EM force - momentum is conserved
- due to the exchange of virtual photons (Feynman)
- Weak nuclear force
- causes a neutron to change to a proton, or a proton to change to a neutron
- W bosons
- have a non-zero rest mass
- have a range of no more than about 0.001fm
- are positively charged or negatively charged
- Beta decay
- W- decays to a B- and an antineutrino
- W+ decays to a B+ and a neutrino
- Electron capture
- proton in a proton rich nucleus turns into a neutron as a result of interacting through the weak interaction
- W+ changes the electron to a neutrino
- the same can happen when a proton and an electron collide at very high speed
- for an electron with sufficient energy, the overall change could occur as a W- exchange from the electron to the proton
- EM force - momentum is conserved
- Inside the atom
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