particles and radiation

Question 1

what are the constituents of the atom and where are they located

Answer 1

• proton (nucleus)
• neutron (nucleus)
• electron (orbitals)

Question 2

what is specific charge

Answer 2

charge per unit mass

Question 3

what are the parts of the AZX notation

Answer 3

A - nucleon number
Z - proton number
X - element

Question 4

what is an isotope

Answer 4

same number of protons
different number of neutrons

Question 5

what is carbon-14 used for

Answer 5

carbon dating

Question 6

separation of nucleons (SNF)

Answer 6

<0.5fm - repulsive
<3fm - attractive

Question 7

what are the nucleon and proton number for alpha and beta decay

Answer 7

alpha - 4 (n) + 2 (p)
beta - 0 (n) + -1 (p)

Question 8

what is the equation for beta minus decay

Answer 8

daughter nucleus + beta minus particle + antineutrino

Question 9

what is the equation for beta plus decay

Answer 9

daughter nucleus + beta plus particle + neutrino

Question 10

what is annihilation

Answer 10

when an particle and an antiparticle collide, and their masses are converted into energy

Question 11

what happens to the energy produced in annihilation

Answer 11

it is released in the form of two photons in opposite directions to conserve momentum

Question 12

give one example of an application of annihilation

Answer 12

a PET scanner, which allows 3D images of the inside of the body to be taken

Question 13

what is pair production

Answer 13

when a photon is converted into an equal amount of matter and antimatter

Question 14

when does pair production occur

Answer 14

when the photon has an energy greater that the total rest energy of both particles

Question 15

what are the four fundamental forces

Answer 15

• electromagnetic
• strong nuclear
• weak nuclear
• gravity

Question 16

what are the exchange particles and what forces do they act on

Answer 16

• gluon (strong nuclear)
• W boson (weak nuclear)
• virtual photon (EM)

Question 17

what interactions is the weak force responsible for

Answer 17

• electron capture
• electron proton collision
• beta decay

Question 18

what is the equation for electron capture and electron proton collision

Answer 18

p + e- = n + Ve

Question 19

properties of hadrons

Answer 19

• experience SNF
• contain quarks
• baryons and mesons

Question 20

properties of leptons

Answer 20

• dont experience SNF
• fundamental
• electron, muon, neutrinos + antiparticles

Question 21

properties of baryons

Answer 21

• contains 3 quarks/antiquarks
• proton, neutron + antiparticles

Question 22

properties of mesons

Answer 22

• quark and antiquark
• pion + kaon

Question 23

what is the most stable baryon, and what does this mean in terms of other baryons

Answer 23

• proton
• means all other baryons will decay into a proton

Question 24

what numbers need to be conserved in interactions

Answer 24

• baryon number
• lepton number
• charge
• momentum
• energy

Question 25

what is the photoelectric effect

Answer 25

when photoelectrons are emitted from the surface of a metal after light above a certain frequency is shone on it

Question 26

what is the relationship between electrons and photons, and how does this effect release

Answer 26

• one electron absorbs one photon
• photoelectron is only emitted if frequency > threshold frequency

Question 27

how does intensity affect photoelectric emission

Answer 27

increased intensity = more photoelectrons being emitted

Question 28

what is work function

Answer 28

minimum energy required for electrons to be emitted off a metal surface

Question 29

what is stopping potential

Answer 29

potential difference needed to apply across metal to stop photons with max Ek

Question 30

equation for stopping potential

Answer 30

Ek(max) = eVs

Question 31

what is excitation

Answer 31

when electrons gain energy from collisions with free electrons and move up in energy level

Question 32

what is ionisation

Answer 32

when an electron gains enough energy to be removed from the atom completely

Question 33

when does ionisation occur

Answer 33

if the energy of the free electron is greater than the ionisation energy

Question 34

give a practical example of excitation

Answer 34

fluorescent tube used to produce light

Question 35

how do mercury atoms become ionised in the fluorescent tube

Answer 35

• voltage accelerates free electrons
• collision with mercury atoms
• causing ionisation

Question 36

what is the result of mercury ionisation

Answer 36

the tube releasing more free electrions

Question 37

what happens when excited mercury atoms de-excite

Answer 37

they release uv photons

Question 38

function of the fluorescent coating

Answer 38

absorbs uv photons

Question 39

what happens when electrons in the fluorescent coating absorb uv photons?

Answer 39

• become excited during absorption
• de-excite and release visible light photons

Question 40

what is an electron volt

Answer 40

energy gained by one electron when passing through a potential difference of one volt

Question 41

what happens when you pass light from a fluorescent tube through a diffraction grating or prism

Answer 41

you get a line spectrum

Question 42

what does each line in a line spectrum represent

Answer 42

different wavelength of light/electron falling to a lower energy level

Question 43

when does absorption line spectra occur

Answer 43

when light with a continuous spectrum passes through a cold gas

Question 44

what does line spectra provide evidence for

Answer 44

electrons in atoms can only transition between discrete energy levels

Question 45

what are examples of light acting as a wave

Answer 45

• diffraction
• interference

Question 46

what are examples of light acting as a particle

Answer 46

• photoelectric effect

Question 47

what are examples of electrons acting as a wave

Answer 47

diffraction pattern

Question 48

what are examples of electrons acting as particles

Answer 48

deflected in electric fields