particles

Question 1

relative mass of electron

Answer 1

1/2000

Question 2

specific charge

Answer 2

charge/mass
Ckg-1

Question 3

which particle has the largest specific charge (PEN)?

Answer 3

e-

Question 4

nucleus forces

Answer 4

strong nuclear force
electric repulsion of protons strains the nucleus but the residual strong nuclear force holds the nucleus together

(EM repulsion> gravity. If there was no attractive force, nucleus would fly apart)

Question 5

strong nuclear force range

Answer 5

short range
repulsive below 0.5 fm (or it would crush nucleus)
attractive between 0.5 and 3 fm

(draw a graph to represent this)

Question 6

voltage

Answer 6

work per unit charge

Question 7

E=mc^2

Answer 7

mass-energy equivalence

mass can be converted to energy in the form of a proton and vice versa
equal amounts matter and antimatter

Question 8

leptons

Answer 8

fundamental particles
do not experience strong force
lepton number +-1
muons decay into electrons

Question 9

hadrons

Answer 9

experience strong force
non-fundamental (made of quarks and anti quarks)
e.g. baryons and mesons

Question 10

baryons

Answer 10

3 quarks
baryon number +- 1

Question 11

stability of baryons

Answer 11

proton is the only stable baryon
free neutron decays into proton in 10 mins

Question 12

quark composition of proton

Answer 12

uud

Question 13

quark composition of neutron

Answer 13

ddu

Question 14

mesons

Answer 14

quark anti-quark pair
pions + kaons
kaons decay into pions
baryon number 0
unstable
discovered in cosmic rays

Question 15

boson

Answer 15

exchange particle

Question 16

fundamental forces

Answer 16

strong
weak
electromagnetic
gravity

Question 17

interaction: strong

Answer 17

boson: gluon (pion)
acts on: hadrons

Question 18

interaction: weak

Answer 18

boson: W+ W- Z
acts on: all particles

changes quark type

Question 19

interaction: E-M

Answer 19

boson: virtual photon
acts on: charged particles

Question 20

interaction: gravity

Answer 20

boson: graviton (theoretical)
acts on: anything with mass

Question 21

Is the interaction possible: E_M

Answer 21

QBLS conserved

Question 22

Is the interaction possible: strong

Answer 22

QBLS conserved

Question 23

conservation

Answer 23

energy
momentum

Question 24

Is the interaction possible: weak

Answer 24

QBLS
strangeness 0,+-1

Question 25

Feynman diagrams

Answer 25

time y position/space x hadrons and leptons on separate sides particles can be denoted by quark composition (for examples see physical flashcards)

Question 26

use of radioactive isotopes: carbon dating

Answer 26

all living things contain same percentage of radioactive carbon-14 taken in from atmosphere after death, carbon-14 decreases over time, decays into stable elements approximate age found using isotopic data

Question 27

strong force between different nucleons

Answer 27

works equally between all nucleons

Question 28

kaons

Answer 28

strange

Question 29

equilibrium position for protons

Answer 29

sum of 2 forces = 0

Question 30

alpha emission

Answer 30

massive nuclei too large, strong force fails Z-2 A-4 short range (cm) -> cloud chamber, geiger counter (count rate drops as you move further away most ionising velocity of alpha particles > velocity of nucleus it is emitted from

Question 31

beta - emission

Answer 31

neutron rich emission of electron and anti neutrino neutron -> proton Z+1

Question 32

beta - evidence for neutrino

Answer 32

energy less than expected conservation of energy neutral particle, almost 0 mass

Question 33

EM spectrum

Answer 33

continuous

Question 34

antiparticle

Answer 34

same mass and rest energy opposite charge

Question 35

rest energy

Answer 35

energy equivalent of particles mass MeV

Question 36

virtual

Answer 36

exists for short amount of time

Question 37

W bosons

Answer 37

large mass (100x proton) exists for a short time cannot travel far photon of zero mass and force with infinite range

Question 38

strange particles

Answer 38

always created in pairs

Question 39

QBLS

Answer 39

charge baryon number lepton number strangeness

Question 40

lepton number

Answer 40

electron and muon numbers should be counted separately

Question 41

quarks

Answer 41

quark confinement -> they do not exist on their own

Question 42

neutrino

Answer 42

tiny mass highly penetrating can pass through the earth without interacting with anything

Question 43

pair production

Answer 43

particle, anti-particle pair one photon converting into energy only gamma ray has enough energy photon reacts near mass ie nucleus

Question 44

EYmin= minimum energy for photon to undergo pair production

Answer 44

2mpc^2 equals the total rest mass of the particles produced Emin=hfmin= 2E0

Question 45

annihilation

Answer 45

collision between particle and anti-particle all mass converted to energy antiparticles usually exist for a fraction of a second before annihilating hence do not exist in ordinary matter

Question 46

annihilation equation

Answer 46

Emin=hf= E0