Particles and Quantum Phenomena

1. Particles and Quantum Phenomena

2. What Are the 4 Fundamental Forces?

3. Fundamental Forces Electromagnetic Gravitational Nuclear weak Nuclear strong

4. Gravity What are/is the exchange bosons? What do they act between? Is it weak or strong?

5. Gravity What are/is the exchange bosons? Gravitons What do they act between? All particles with mass Is it weak or strong? Very weak (it only feels big because the Earth is so big!)

6. Electromagnetic What are/is the exchange bosons? What do they act between? Is it weak or strong?

7. Electromagnetic What are/is the exchange bosons? Photons What do they act between? Charged particles Is it weak or strong? Very strong compared to gravity

8. Nuclear Weak What are/is the exchange bosons? What do they act between? Is it weak or strong?

9. Nuclear weak What are/is the exchange bosons? W+, W-, Z What do they act between? Nucleons Is it weak or strong? Weak (compared to nuclear strong!)

10. Nuclear strong What are/is the exchange bosons? What do they act between? Is it weak or strong?

11. Nuclear strong What are/is the exchange bosons? Gluons What do they act between? Quarks Is it weak or strong? Very strong

12. Particles and Anti Particles All particles have an antiparticle Anti particles have the same ��� But opposite �����

13. Particles and Anti Particles All particles have an antiparticle Anti particles have the same mass But opposite charge What happens if they come across each other?

14. Annihilation This happens when a particle and its antiparticle meet. The result is 2 or 3 Gamma rays are given out and the particles disappear. What is the opposite of Annihilation?

15. Pair production If a gamma Ray interacts with something e.g. an atom/electron and it has enough energy a pair of particles may be produced. The pair consists of one particle and its antiparticle. (The atom/electron has to be there so that momentum is conserved)

16. Observing particles How do we �see� particle collisions annihilations etc?

17. Cloud chambers and Bubble chambers Both of these enable us to see the paths of particles by observing the ionisation caused by the tracks. If a magnetic field is present the tracks are?

18. Particle tracks What could this be?

19. Particle tracks Pair creation Why do they curve different ways?

20. Particle Families What are the main ones?

21. Particle families The main groups are :- Hadrons Leptons

22. Leptons What type of particle are they? What is the simplest?

23. Leptons They are light (relatively small mass) particles The simplest is the electron What are the other three particles that make up the basic family?

24. Basic lepton family Electron e- and Positron e+ Electron neutrino ?e and Anti electron neutrino ?e What about the excited lepton family?

25. Excited Lepton Family Muon � Anti Muon Muon neutrino ?� and Anti Muon neutrino The Tau family is the last in the series but should not be needed!

26. Hadrons What is the basic property?

27. Hadrons These are heavy (e.g. contain a relatively big mass) They are made from Quarks But what are the two sub sets?

28. Hadrons They are split into two sub sets:- 1 Baryons 2 Mesons What is the difference?

29. Baryons and Mesons Baryons are made up of three Quarks Mesons are made up of two Quarks (one normal and one anti quark) What are the common Baryons?

30. Baryons Neutrons, protons, sigma's S, omegas O And their anti particles All of these have a baryon number of 1 or �1 What about the mesons? What are the common ones?

31. Mesons These are made of two quarks one quark and one anti quark There are p mesons (often called pions) And ? mesons (often called Kaons) They may have charge of +1, -1 or 0

32. Quarks What are they? What types are there? What properties do they have?

33. Quarks What are they? Fundamental particles! What types are there? Up, down, strange, charm, top and bottom. (These are sometimes called flavours of quark!) There are also anti-quarks which have opposite charge. What properties do they have? Mass, charge, baryon numbers of 1/3 or 2/3 and lepton numbers of 0!

34. Conservation Laws Lepton number is ���.. conserved. Baryon number is ���.. conserved. Charge is ���� conserved. Strangeness �����. But���������..

35. Conservation Laws Lepton number is ALWAYS conserved. Baryon number is ALWAYS conserved. Charge is ALWAYS conserved. Strangeness CAN change but only in weak decays.

36. Feynman Diagrams Sorry you have just got to learn them! But what don�t they show us?

37. Feynman Diagrams They DON�T show DIRECTION Have you learnt them?

38. Refraction When light passes from one material to the other, which of the following changes? Wavelength Speed Direction Frequency Colour

39. Refraction When light passes from one material to the other the following things happen:- Wavelength Changes Speed Changes Direction Changes (if not at 00 !) Frequency Stays the same Colour Stays the same

40. What about Air to Glass Do the following increase or decrease? Wavelength Speed Direction Frequency

41. Air to glass(optically less dense to dense) Wavelength Shortens Speed Slows Direction Refracted TOWARDS the Normal Frequency Stays the same

42. Glass to Air(Optically More Dense to Less Dense) Wavelength increases Speed increases Direction refracted AWAY from the normal Frequency stays the same

43. Snell�s Law This shows us the relation ship between the speeds and the sine of the angles of incidence and refraction. What is it?

44. Snell�s Law 1n2 = sin i = c1 speed in material 1 sin r c2 speed in material 2 Refractive index going from material 1 to 2

45. Refractive index going from two different materials Eg from glass to water How could you work it out?

46. Refractive index going from two different materials Eg from glass to water Yes you divide one refractive index by the other but which way round?? What is the formula?

47. 1n2 = n2 / n1 Eg Water n = 1.33 Glass n = 1.54 So refractive index from water to glass :- wng = 1.54/1.33

48. The critical angle? What is it all about and why is it so critical?

49. The critical angle This is the maximum angle of incidence that light can be refracted and pass through a boundary! Eh?

50. Remember the diagram!

51. How about the equation?

52. Sin ?c = 1/n

53. Don�t forget Total internal reflection only happens trying to go from more dense to less dense. Also if you do 1/n and inverse sine on your calculator and you get an error you have got the wrong n!!! Just invert the number you�ve got!

54. You need to explain about :- Optical fibres The cladding ( lower refractive index surrounding the higher refractive index core) Modern applications in:- Endoscopy communications

55. The Photoelectric Effect What is incident on the metal surface? What comes out from the surface?

56. The Photoelectric Effect What is incident on the metal surface? Photons What comes out from the surface? Photoelectrons

57. What about energy? What gives up its energy? Where does it go?

58. What about energy? What gives up its energy? The Photon Where does it go? To remove the photoelectron and give it Kinetic energy What is the Nobel prize winning equation?

59. Einstein's Photoelectric Equation Energy of Photon (E = hf) hf = F + Ek Work function Maximum Kinetic energy

60. What is the work function etc?

61. F = the work function or the energy required to remove an electron from the metals surface.

62. What happens if you change the conditions? Eg if the intensity of light is increased? What happens to the number of photons? What happens to the maximum kinetic energy?

63. What happens if you change the conditions? Eg if the intensity of light is increased? What happens to the number of photons? It increases! What happens to the maximum kinetic energy? It stays the same! The frequency stays the same!

64. What happens if you change the conditions? Eg if the frequency of the light is decreased? What happens to the number of photons? What happens to the maximum kinetic energy?

65. What happens if you change the conditions? Eg if the frequency of the light is decreased? What happens to the number of photons? It stays the same! (The intensity is the same) What happens to the maximum kinetic energy? It decreases. (there is less energy contained in EACH photon so less available for EACH photoelectron)

66. What if the frequency is really low? As the frequency gets lower the maximum kinetic energy of each photoelectron gets lower until���.

67. What if the frequency is really low? As the frequency gets lower the maximum kinetic energy of each photoelectron gets lower until���. There is no longer enough energy available to overcome the work function. The result is no photoelectrons are ejected. The lowest frequency possible is called the threshold frequency.

68. The electronvolt First a quick reminder of the definition of a volt:- 1 Joule is the work done moving one coulomb of charge through one volt. Or Energy = Charge x Voltage

69. So what about the electronvolt? This is the energy required to accelerate one electron through one volt! But E = Q x V So 1eV = 1.6 x 10 �19 J Or 1J = 1/1.6 x 10 �19 eV�s

70. Energy Levels in Atoms All ���.. in atoms are held in fixed precise energy levels. Each electron is in a ���.. energy level. Electrons cannot occupy the same �� as another electron. When electrons �Jump� between levels an ��.. amount of energy is given out or taken in.

71. Energy Levels in Atoms All electrons in atoms are held in fixed precise energy levels. Each electron is in a different energy level. Electrons cannot occupy the same level as another electron. When electrons �Jump� between levels an exact amount of energy is given out or taken in.

72. Evidence That Suggests This Line spectra (Eg Sodium lamp) The light given out is of an exact wavelength and frequency. This corresponds to an exact change in energy of an excited electron from a high level to a lower level.

73. What Is the Equation That Enables Us to Work Out the Frequency Given Out?

74. hf = E1 � E2 hf = energy of photon given out E1 = Energy of electron level 1 E2 = Energy of electron level 2

75. Uses of excitation You need to know about ionisation and excitation in the fluorescent tube. Look it up if you don�t!!

76. Thought I�d Save the Impossible to Last! Read on unless you are schizophrenic!! Sorry did someone say something?

77. Wave Particle Duality So you though everything is a wave or a particle yeh? Well life is not that easy in fact its totally impossible to understand!! Don�t give in though the equation is easy even if the end result is quantum mechanics that NOBODY understands!

78. de Broglie and his wavelength de Broglie postulated that every particle exhibits wavelike behaviour but that all waves also exhibit particle like behaviour. (waves are particles and particles are waves!)

79. What is the equation? ? = h/mv ? = Wavelength associated with particle of momentum mv h = Planck�s constant.

80. You Need to Remember That Electron Diffraction Through Layers of Graphite Atoms Give Us Evidence of the Wavelike Behaviour of Electrons.

81. That�s All Folks!