Nuclear and Particle physics
-Made up of 2 protons and 2 neutrons -Emitted from the nuclei -Can travel a few cm in air -Bends towards the negative charge in an electric field so is shown to be positively charged.
Alpha radiation, what is it composed of, what emits it , how far can it travel, how does it react in a electric field.
-An electron,e⁻, or positron,e⁺. -A nucleon under going beta decay, emits beta particle n->p+e⁻+V β⁻decay p->n+e⁺+V β⁺decay e+p->n+V electron capture -Can't penetrate more than a few cm of aluminium -Bends towards the positive charge in an electric field so i shown to be negatively charged, also bends more than α, so it is lighter
Beta radiation, what is it composed of, what emits it(describe the processes) , how far can it travel, how does it react in a electric field.
Activity- measured in Becquerel (Bq) defined as 1Bq= Decay/second Absorbed dose-Meaured in Grays (Gv) defined as 1Gy=1J absorbed per kg of material Biological effect of radiation- Equivalent does=absorbed dose x Relative biological effectiveness measured in sieverts 1sv=Dose(Gy) x RBE
Define Activity, Absorbed dose and Biological effect of radiation
mean: x= (∫xf(x)dx)/(∫f(x)dx mean life time,τ=(∫tλexp(-λt)dt)/(∫λexp(-λt)dt) =(1/λ)/1=1/λ so τ=1/λ so N(t)=N₀exp(-t/τ)
Derive the mean life time
Atom X captures an electron, in the process it emits a neutrino, so new atom Y has one more electron and neutron and one less proton than atom X
Describe Electron capture
atom X undergoes alpah emission. It losses 2 protons and 2 neutrons. Its mass is receded by 4, its atomic number is reduced by 2. A helium ion is emitted, i.e. 2 protons 2 neutrons
Describe a Alpha emission
β⁻ = Atom X emits an electron and an anti neutrino (neutron turns into proton) so the new atom Y has one more proton and one less neutron than atom X β⁺= Atom X emits a positron and a neutrino (proton turns into neutron) so the new atom Y has one less proton and one more neutron than atom X
Describe the what a β⁻ decay and a β⁺ decay is
Acts between all particles or objects with mass, has an invite range and the force mediator is the graviton Force, F=Gm₁m₂/r² Potential, V=-Gm/r
Explain Gravitational Force and the equation for force and potential
There is the same amount of ¹⁴C in a living organism as the environment around them. ¹⁴C decays to ¹²C. When an organism dies the ¹⁴C decays but isn't replenished as it would be in a living organism. So we can use the ratio of ¹⁴C to ¹²C N(¹⁴C)/N(¹²C)=γ=γ₀exp(-λt) t=1/λln(γ₀/γ) where γ₀ is the ratio of ¹⁴C to ¹²C in the atmosphere (1.8x10⁻¹²)
Explain carbon dating and how to calculate the time that past
Electromagnetic force occurs between two charged particles, it has an infinite range is the force mediator is photons Force, F=-Q₁Q₂/4πε₀r² Q is charge potential, V=Q/4πε₀r
Explain electromagnetic force and state the equations for the force and the potential
It combines nucleons and nuclei together, it acts between all hadrons and has a finite range, All particles that interact strongly are called Hadrons. The two variants are Fundimental- The strong interaction that acts between quarks and gluons i.e between colour charges Residual- Strong force acts between protons and neutrons and binds atomic nuclei together
Explain the strong interaction and what are the two variants
Acts between all fundamental particles apart form force carriers. Although it is weak it is important if the strong interaction is forbidden by some conservation laws or the particle is neutral It is responsible for β decay Mediated by change of W± and Z⁰ Bosons
Explain the weak interaction
-High energy photon -Emitted from a nucleon when they change energy state -Highly penetrate , stopped by several cm of lead. -Doesn't bend in the electric or magnetic field showing it is neutral.
Gamma Radiation,what is it composed of, what emits it, how far can it travel, how does it react in a electric field.
Q=(Ma+Mb)C²-(Mc+Md)C² if Q>0 reaction is exothermic if Q<0 reaction is endothermic
If atoms A and B undergo a reaction and produce atoms C and D, how can you calculate the energy released in that reaction,Q.
Charge- The sum of all the charges in the initial and final state is the same, charge is conserved in all interactions Baryon number- The number of baryons minus the number of anti baryon, conserved in all interactions Lepton flavour- electron,muon,tau. conserved in all interactions except neutrino oscillations Quark flavour- up, down, strange, charm, top, bottom conserved in all interactions apart from the weak interactions.
State what Charge, Baryon number, Lepton flavour and Quark flavour are, and determine when they are conserved and when they are not
Two fermions can not occupy the same quantum state, They 'occupy space' and follow fermi-dirac statistics and they make up matter Many bosons can occupy the same quantum state, follow Bose-Einstein statistics, and make up the force carriers and mesons
The pauli exclusion pricniple dictates that fermions and bosons have to behave fundamentally different, what are these differences
Baryons const of three quarks or 3 anti quarks and have a possible charge of -2,-1,0,+1,+2 Example , Proton, 2U 1D so Q= ⅔ +⅔-⅓ =overall charge of +1 , Neutron 1U 2D so over all charge Q=⅔-⅓-⅓=0
What are Baryons, give examples
Quarks come in 6 flavours , Up(u), Down(d), strange (s), charm (C) , top (t) and bottom (b) The quarks come in pairs U=+⅔ D=-⅓ ,S=-⅓ C=+⅔ , T=+⅔ B=-⅓ all quarks also have an anit quark with an opposite charge (shown with a line over the symbol) -U=-⅔ -D=+⅓ ,-S=+⅓ -C=-⅔ , -T=-⅔ -B=+⅓
What are Quarks, name the quarks and state their charge
Particles that are not interacting strongly (i.e. not using the strong interaction)(like quarks each flavour has a partner Flavours: electron (e) electron neutrino(Ʋe), muon (µ) muon neutrino(Ʋµ), tau(τ) tau neutrino (Ʋτ)
What are leptons, and name the flavours of leptons
Strong, weak, electromagnetic and gravitational
What are the 4 fundamental forces
they unify to make the electroweak interaction em is mediated by massless photon weak force mediated by W± and Z⁰
What happens to the weak and electromagnetic force at high temperatures
Energy is realised by splitting heavy elements into light er metals a neutron is fired at a heavy atom, the atom splits into two smaller atoms and also releases 2 neutrons, these neutrons go and repeat the process Critical mass - the mimic mass of fissile material that gives a substantial fission reaction
What is Nuclear Fission and what is critical mass
Two or more atomic nuclei fuse together to form a single heavier nucleus, releases large quantities of energy plus neutrons and possibly helium. Caused at high temperatures or high densities, as an electrostatic barrier has to be overcome
What is Nuclear Fusion
It is a diagram used to describe the actions of electrons and photons during different interactions
What is a Feynman Diagram
Concepts of a quark and an anti-quark ,possible charge -1,0,+1 example pion,π⁺ 1U 1-D(anti down) over all charge Q=⅔+⅓=1, Kaon,K⁰, 1D 1S(anti strange) over all charge Q=-⅓+⅓=0
What is a meson
Isotope- 2 nuclei with the same number of protons but different number of neutrons Isotones-Nuclei with the same number of neutrons but different number of protons Isobars: same mass but different number of both protons and neutrons
What is an Isotope, isotone, isobar
E²=p²c²+m²c⁴
What is relativistic energy of a particle
P=M₀γV=M₀V/√(1-u²/c²) E=M₀γC²= M₀C²/√(1-u²/c²)
What is relativistic momentum and energy
A(t)=A₀exp(-λt), activity decreases with time
What is the activity
Fermions have an odd half integer spin i.e. ½,3/2.. Leptons, quarks and Byrons(proton, neutron) are fermions Bosons have an integer spin ie ( 1,2,3..) All force carriers are bosons and some mesons The spins are measured in units of ħ (ħ=h/2π)
What is the difference between Fermions and Bosons and give examples for both
There is a difference in the mass measured of an atom and the sum of the masses of it's constituents. Mass defect= Matom -Zmp-Nmn-Zme where Z is the number of protons/electrons and N is the number of neutrons Mass defect and the masses of the protons, neutrons,etc.. are measured in atomic mass units, u. 1u=1.66054x10⁻²⁷Kg. ( rest mass of proton)
What is the mass defect
If there was N₀ at t=0 then the number of nuclei at time t N(t)=N₀exp(-λt) The decay probability per unit per time per nucleus is constant the dN/dt α N , so dN/dt=-λN (where λis a constant) we then rearrange the so the N terms are on the same side so dN/N=-λdt so integral both sides ∫dN/N=∫-λdt The n integral goes from N₀(number of nuclei to begin with) to N(number of nuclei at time t) The t integral goes from t=0 to some time t after integration Ln(N)-Ln(N₀)=-λt Ln(N/N₀)=-λt --> N=N₀exp(-λt)
What is the radioactive law and what is the derivation.
If we imagine A is a beam particle and B is a stationary target, and they produce atoms C and D All particles have mass, ACD have kinetic energy and momentum. First we transfer to a centre of mass frame, where the CoM frame is moving with respect to the lab frame and the total momentum is 0 and Kc=Kd=0 the velocity of the CoM frame is u=MaVa/(Ma+Mb) U is then taken away from the velocities of A and B in the lab frame to convert them to the CoM frame Ka+Kb=½Ma(Va-U)²+½MbU²=-Q the threshold energy is Kth Kth=MaVa²/2 Kth=-(1+(Ma/Mb))Q
What is threshold energy
electron- solid line with an arrow pointing from left to right Positron- Solid line with an arrow pointing right to left fermion- a solid line boson- wiggly line photon- wiggly line without arrow quarks- represented with symbol i.e. up(u). if it's a nuetron there will be an n and inside a bracket will be the quarks that it contains i.e. n{UDD
When drawing a Feynman diagram how would your draw an electron, positron, fermion, boson, photon and quarks
The time taken for the number of nuclei to half N=N₀exp(-λt) at half life N=N₀/2 N₀/2=N₀exp(-λt) ½=exp(-λt) -λt=ln(1)-ln(2) λt=ln(2) t=ln(2)/λ= τln(2)
define and derive half life