AS - Particles And Radiation Flashcards

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1
Q

Equilibrium point for strong nuclear force

A

0.5 fm

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2
Q

Maximum attraction for strong nuclear force

A

2 fm

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3
Q

Nucleus Diameter

A

3 - 4 fm

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4
Q

Alpha Decay

A

4 He 2 nucleus
decays to give out mass
short range (5cm in air)

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5
Q

Beta - Decay

A

0 e -1 fast moving electron
Decays to change n -> p
Releases an antineutrino (takes away energy and momentum)

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6
Q

Beta + Decay

A

0 e +1 fast moving positron
Decays to change p -> n
Releases a neutrino (takes away energy and momentum)

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7
Q

Gamma Decay

A

Has no mass or charge (it’s a wave)

Decays to give out energy

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8
Q

Neutrinos

A

Conserves energy in beta decays
Has no charge and almost no mass
1930 - Wolfgang Pauli found the neutrino
1955 - Neutrino was observed

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9
Q

Atomic Structure

A

A Na Z
A = p + n (nucleon number)
Z = p = e (proton number)

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10
Q

Isotopes

A

Same proton number, different nucleon number

Same number of protons, different number of neutrons

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11
Q

Specific Charge

A

Specific Charge (C/kg) = Charge (C) / Mass (kg)

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12
Q

Proton Charge and Mass

A

p+

  1. 6x10-19 C
  2. 67x10-27 kg
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13
Q

Neutron Charge and Mass

A

n
0 C
1.67x10-27 kg

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14
Q

Electron Charge and Mass

A

e-

  • 1.6x10-19 C
    9. 11x10-31 kg
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15
Q

Photons Equations

A

EM radiation exists as photons
Energy (J) = Planck’s Constant (Js) x Frequency (Hz)
Energy (J) = Planck’s Constant (Js) x Speed (m/s) / Wavelength (m)

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16
Q

Proton and Antiproton Rest Energy

A

938MeV

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17
Q

Neutron and Antineutron Rest Energy

A

939MeV

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18
Q

Electron and Positron Rest Energy

A

0.511MeV

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19
Q

Neutrino and Antineutrino Rest Energy

A

0MeV

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20
Q

J to eV and eV to J

A

J to eV - divide by 1.6x10-19
eV to J - multiply by 1.6x10-19
eV is the work done when an electron moves through a pd of 1V

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21
Q

Pair Production

A

E min = hf min = 2E
1 photon : 1 particle
Produces particle and antiparticle
Energy (photon) -> mass (e+ and e-)

22
Q

Annihilation

A
E min = hf min = E
Produces energy (photons)
Mass (e+ and e-) -> Energy (2 x photons)
23
Q

Electron Capture

A

p+ + e- -> n + Ve
W+ boson
Arrow from proton to electron

24
Q

Electron - Proton Collisions

A

e- + p+ -> n + Ve
W- boson
Arrow from electron to proton

25
Q

Electromagnetic Force

A

Virtual photon
Affects all charged particles
Infinite range

26
Q

Weak Nuclear Force

A

W+ and W- bosons
Affects all particles
Short range

27
Q

Strong Nuclear Force

A

Pions
Affects hadrons only
Short range

28
Q

Gravitational Force

A

Graviton
Affects anything with mass
Infinite range

29
Q

Up Quarks

A

Charge = 2/3
Strangeness = 0
Baryon number = 1/3

30
Q

Anti Up Quarks

A

Charge = -2/3
Strangeness = 0
Baryon number = -1/3

31
Q

Down Quarks

A

Charge = -1/3
Strangeness = 0
Baryon number = 1/3

32
Q

Anti Down Quarks

A

Charge = 1/3
Strangeness = 0
Baryon number = -1/3

33
Q

Strange Quarks

A

Charge = -1/3
Strangeness = -1
Baryon number = 1/3

34
Q

Anti Strange Quarks

A

Charge = 1/3
Strangeness = 1
Baryon number = -1/3

35
Q

Lepton Rules

A

Lepton number must be conserved
e- can only produce Ve
Muon- can only produce Vmuon

36
Q

Conservation Rules

A

Energy and charge must be conserved (all reactions)
Lepton numbers must be conserved
Strangeness must be conserved (strong force reactions)
Baryon numbers must be conserved

37
Q

Hadrons

A

Strong force

Baryons and mesons

38
Q

Baryons

A

QQQ
Proton (uud)
Neutron (udd)

39
Q

Mesons

A

Qq
Pion
Kaon

40
Q

Leptons

A
Fundamental
Weak force
Muon
Electron 
Tau
Neutrinos
41
Q

Stopping Potential

A

Minimum V needed to stop electron emission (Vs)
At Vs, Ek = 0
Ek max = eVs
e = electron charge

42
Q

Vacuum Photocell

A

When f > f min in incident light, electrons from cathode are attracted to anode
Ammeter measures photoelectric current
I is proportional to electrons per second
Number of electrons = I / e

43
Q

Photoelectric Effect In A Photocell

A

Each photo electron can only absorb one photon
Intensity = number of photons
Ek max = hf - ø

44
Q

Work Function (ø)

A

Electrons can leave a metal’s surface if E > ø
f min = ø / h
Excess energy = Ek
Power of a beam P = nhf

45
Q

Photoelectric Effect Conditions

A

Incident EM radiation must have f > f min
Frequency depends on metal (f = c / wavelength)
Intensity does not affect electron emission (no delay)

46
Q

Ionisation

A

p =/= e
Adding electrons = -
Removing electrons = +

47
Q

Excitation

A

Energy is absorbed from colliding electrons without electrons leaving the atom
Energy levels are discrete and only happens at those values
Excitation energy < ionisation energy

48
Q

Energy Levels

A
Lowest = ground state
Energy = energy level value 
E of emitted photon = E1 - E2
Uses E from incoming photon
Electrons de excite (fall down energy levels) and release a photon
49
Q

Fluorescent Tubes

A

Tube contains mercury vapour at low pressure
Power supply => mercury atoms collide and cause ionisation and excitation
Mercury releases UV photons, they’re absorbed by coating and excite
UV de excites to release visible photons

50
Q

Line Spectra

A

Every atom has a different composition

Each line of colour corresponds to an energy level

51
Q

Wave - Particle Duality

A

Wave - diffraction (spreads out in waves)

Particle - photoelectric effect (1:1 with immediate emission)

52
Q

De Broglie Wavelength

A

Wavelength = h / mv
Electron diffraction - electrons are fired through a thin foil slit and spread out producing circles on a screen
pd + = v + = rings - = wavelength - = diffraction -
Electrons diffract by the same amount at the same angle