Particles

Question 1

Atom

Answer 1

An electrically neutral collection of electrons, protons and neutrons. The number of electrons is equal to the number of protons.

Question 2

Element

Answer 2

A substance that can’t be broken down by chemical means into simpler substances.

Question 3

Nucleon

Answer 3

A particle that makes up the nucleus- either a proton or a neutron.

Question 4

Nucleon number (A)

Answer 4

The total number of nucleons in the nucleus (protons + neutrons) - mass number

Question 5

Ion

Answer 5

An atom that has gained or lost one or more outer electrons leaving its charge unbalanced

Question 6

Nuclide

Answer 6

The nucleus of a unique atom that is one with a specific number of protons and neutrons

Question 7

Isotope

Answer 7

Elements with different numbers of neutrons but the same number of protons. Have similar properties to the element but are normally radioactive

Question 8

Proton number (Z)

Answer 8

The total number of protons present in the nucleus - atomic number

Question 9

Specific charge formula

Answer 9

Actual charge / actual mass

Total protons) x (charge of proton)/(number of nucleons)x(mass of nucleon

Question 10

Specific charge of an atom

Answer 10

0

Question 11

What has the biggest specific charge? A proton or an electron?

Answer 11

Electron.

They have a smaller mass than a proton (sc=charge/mass)

Question 12

Strong nuclear force

Answer 12

Force which holds the nucleus together and stops protons from repelling

Question 13

What is alpha decay?

Answer 13

A helium nucleus of +2 charge and mass of 4AMU
(2 protons 2 neutrons)

Happens in atom with very large mass number

Question 14

What is beta minus decay?

Answer 14

A fast moving electron of single negative charge and mass 1/1860 AMU.
(n > p + e)

Happens in a neutron rich nucleus

Question 15

What is beta plus decay?

Answer 15

p > n + e(+)

Happens in a proton rich nucleus

Question 16

What is gamma decay?

Answer 16

A photon of energy (wave) with no charge or mass. Released to channel away energy (get rid of excess energy).

Question 17

What is a neutrino?

Answer 17

Has no charge and a very small mass. Millions pass through your body every second but don’t interact

Question 18

How does light travel?

Answer 18

As photons (packets of energy)

Question 19

Formula for energy of a photon

Answer 19

E = hf
or
E=hc/wavelength

Question 20

What is an antiparticle?

Answer 20

Every particle has an antiparticle which has the same mass but the opposite charge

Question 21

1MeV in joules?

Answer 21

1.6x10-13 J

Question 22

What is rest energy?

Answer 22

The amount of energy needed to make one of these particles/ the amount of energy released is the particle is destroyed

Question 23

What is annihilation?

Answer 23

If a particle and its antiparticle meet they destroy each other and produce photons of energy

Question 24

What is pair production?

Answer 24

Making a particle and its antiparticle with enough energy (normally from a gamma photon)

Question 25

What is the electromagnetic force?

Answer 25

Force between 2 charged objects due to the exchange of virtual photons (attraction and repulsion). One particle emits and the other absorbs it (exchanging momentum).

Question 26

What does the electromagnetic force act on?

Answer 26

Quarks, charged leptons, W+ W-

Question 27

What is the weak nuclear force?

Answer 27

Force created in radioactive decay of subatomic particles. Mediated by W+ or W- bosons

Question 28

What does the weak nuclear force act on?

Answer 28

Quarks and leptons

Question 29

What is the strong nuclear force?

Answer 29

It holds the nucleus together, stops protons from repelling and stops protons and neutrons from squashing into each other.

Question 30

What is the strong nuclear force carried by?

Answer 30

Gluons

Question 31

What does the strong nuclear force act on?

Answer 31

Quarks and gluons

Question 32

Feynman diagram for B- decay

Answer 32

n -> p + e- + Ve_ Occurs via weak interaction Mediated by W- boson

Question 33

B+ decay

Answer 33

P -> n + e+ + Ve Occurs via weak interaction Mediated by W+ boson

Question 34

Electron capture

Answer 34

P + e- -> n + Ve Occurs qua weak interaction Mediated by W+ boson

Question 35

Neutrino-neutron collision

Answer 35

N + Ve -> p + e- Occurs via weak interaction W- boson

Question 36

Antineutrino-proton collision

Answer 36

P + Ve_ -> n + e+ Weak interaction W+ boson

Question 37

Electron-proton collision

Answer 37

e- + p -> n + Ve Weak W- boson

Question 38

Quark

Answer 38

A fundamental and subatomic particle that combines with other quarks to form hadrons

Question 39

Lepton

Answer 39

A subatomic particle which doesn't take part in strong interactions (electron, muon, tau or neutrino) Light and fundamental Experience weak force If charged interact via weak/electromagnetic

Question 40

Gauge bosons

Answer 40

Force carriers. Elementary particle interact by exchange of gauge bosons.

Question 41

What are the quark flavours?

Answer 41

Up + down Charm + strange Top + bottom

Question 42

What is the quark structure of a proton?

Answer 42

uud

Question 43

What is the quark structure of a neutron?

Answer 43

udd

Question 44

What is the general quark structure of Baryons?

Answer 44

3 quarks

Question 45

What is he general quark structure of anti-baryons?

Answer 45

3 anti-quarks

Question 46

What is the general quark structure of mesons?

Answer 46

Quark- antiquark pair

Question 47

What is a hadron?

Answer 47

Have quarks inside Heavy, not fundamental Experience strong force but decay via weak force

Question 48

What is a baryon?

Answer 48

Bigger hadron (proton or neutron)

Question 49

What is a meson?

Answer 49

Medium hadron (pi mesons, k mesons)

Question 50

What is the conservation of charge?

Answer 50

Q before = Q after

Question 51

What is the conservation of lepton number?

Answer 51

L before = L after

Question 52

What is the conservation of baryon number?

Answer 52

B before = B after

Question 53

What is the conservation of strangeness?

Answer 53

Strangeness is conserved in strong and electromagnetic interactions. Not conserved in weak interactions (increases/decreases by 1)

Question 54

1fm in m?

Answer 54

X10-15 m

Question 55

Formula for total energy

Answer 55

Total energy = number of photons x energy of one photon

Question 56

What quantity changes continuously in moving from the bottom to the top of a Feynman diagram?

Answer 56

Time