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What is an exchange particle?
A virtual particle that lets a force act between 2 particles in an interaction.
What is another term for exchange particles?
Gauge bosons.
How can you tell whether it is a Strong or Weak interaction?
If leptons involved and/or strangeness not conserved (0,-1,+1)= WEAK
If hadrons & strangeness conserved = STRONG
What is the difference between electron capture and electron-proton collisions?
In electron capture, a proton within a nucleus captures an electron from the atom, turning into a neutron and also emitting a neutrino.
In electron-proton capture, a free electron is fired at a free proton and collides with it, producing a neutron and a neutrino.
What interaction creates strange particles?
Strong interaction
What are the letters form both Nucleon Number and Proton Number?
Nucleon number: A
Proton number: Z
Explain how radioactive carbon-14 can be used to find the age of a fossil. (3 marks)
All living organisms have the same amount of carbon-14 atoms as a percentage of all carbon isotopes.
Once the organism dies, it no longer absorbs carbon from the atmosphere.
Carbon-14 is radioactive and so will decay over a known half life.
(The older the fossil is, the fewer carbon-14 isotopes it will contain and the less radiation it emits.)
The distance at which the strong nuclear force becomes repulsive is about what?
0.5fm and under
Why was the Antineutrino hypothesised? (5 marks)
When scientists first observed beta decay, they thought that neutrons were decaying into a proton and an electron only.
They noticed that the energy of the neutron before the decay was larger than the energy of the proton and electron after the decay: energy was not being conserved.
To account for this, scientists hypothesised that a new type of particle was being produced and carrying away some energy.
This particle must have zero (or almost zero) mass and must be electrically neutral (to obey charge conservation).
This particle was then called a neutrino but we now know it to be an antiparticle called an antineutrino.
What are exchange particles sometimes also called?
Gauge bosons
What is the exchange particle of the strong nuclear force between quarks?
Pion/Gluon
What do kaons decay into and by what interaction?
Pions
Weak interaction with the W+ boson.
What do muons decay into?
Electrons
Note 
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