Particles and Radiation Flashcards
What is the charge of an electron?
-1.6x10^-19
What is the charge of a proton?
+1.6x10^-19
What is the charge of a neutron?
0
What is the mass of a proton?
1.67x10^-27
What is the mass of a neutron?
1.67x10^-27
What is the mass of an electron?
9.11x10^-31
What is specific charge?
The ratio of charge to mass
What is the equation for specific charge?
Charge / mass
What are the four forces that act inside the nucleus?
Strong force
Electromagnetic force
Gravitational force
Weak force
What is the relative strength of the strong force?
1
What is the relative strength of the weak force?
10^-6
What is the relative strength of the electromagnetic force?
1 / 137
What is the relative strength of the gravitational force?
10^-39
What is the range of the strong force?
3 fm or 10^-15
What is the range of the electromagnetic force?
Infinite
What is the range of the weak force?
10^-18
What is the range of the gravitational force?
Infinite
When can alpha decay occur?
Occurs only in large atoms because they are unstable.
What is the nucleon number?
Number of protons + number of neutrons
What letter can be used to represent the nucleon number?
A
What is an isotope?
An atom with the same number of protons and electrons but a different number of neutrons.
What is a radioisotope?
An isotope that is radioactive.
What is carbon-14 used in?
Carbon dating.
What is specific charge used in?
Mass spectrometry to identify nuclei.
What are the units of specific charge?
Ckg^-1
What is each type of nucleus called?
A nuclide
What is 1fm in m?
1x10^-15 m
What does the strong force act between?
Nucleons (e.g. protons and neutrons)
Is the strong force attractive or repulsive?
Both
Why is the strong force both attractive and repulsive?
Otherwise the nucleus would collapse or explode.
When is the strong force attractive?
> 0.5fm
When is the strong force repulsive?
<0.5fm
For light nuclei, what is the ratio of protons to neutrons?
Proton number = Neutron number.
The two particles must exist together
For heavy nuclei, what is the ratio of protons to neutrons?
More neutrons that protons (and very large nuclei and radioactive)
What is equilibrium separation?
A point where the resultant force is 0 and the attractive and repulsive forces balance.
What force is responsible for beta decay?
The weak force.
How strong is the weak force?
1 millionth the value of the strong force.
How does the range of the weak force compare with that of the strong force?
It has a smaller range.
What does the weak force act on?
Hadrons and leptons.
What is annihilation?
It is where a particle and its corresponding anti-particle collide, and as a result their masses are converted into energy.
What is an application of annihilation?
PET scanner (Allows 3D images of inside the body to be taken)
- It is done by introducing a positron-emitting radioisotope into the patient. As positrons are released, the positrons annihilate with electrons already in the patients system, emitting gamma photons which can easily be detected.
What is pair production?
It is where a photon is converted into an equal amount of matter and antimatter.
What is the equation for electron capture?
proton + electron –> neutron + electron neutrino
Exchange particle is W+
What is the equation for electron-proton collision?
proton + electron –> neutron + electron neutrino
Exchange particle is W-
What is the equation for beta minus decay?
neutron –> proton + electron + anti-electron neutrino
Exchange particle is W-
What is the equation for beta plus decay?
proton –> neutron + positron + electron neutrino
Exchange particle is W+
Do leptons experience the strong nuclear force?
No only hadrons feel the strong force.
What is a baryon?
A particle made up of 3 quarks.
What is a meson?
A particle made up of 1 quark and 1 anti-quark.
What are the 4 laws of conservation?
- Charge must be conserved
- Lepton number must be conserved
- Baryon number must be conserved
- Strangeness must be conserved in strong interactions but can be, 0, +1, or -1 in weak interactions.
What is the quark composition of π+ ?
_
ud
What is the quark composition of π0 ?
uu or dd or ss
What is the quark composition of π- ?
_
du
What is the quark composition of k+ ?
_
us
What is the quark composition of k0 ?
_
ds
What is the quark composition of k- ?
_
us
