An electron and a positron (antielectron), both nearly at rest, collide. What particle(s) is (are) produced?

1. 1. 2. 3. 4. An electron and a positron (antielectron), both nearly at rest, collide. What particle(s) is (are) produced? • Two photons of energy 511 keV • One photon of energy 1.02 MeV • A pi-meson and an anti-neutrino • A K-meson

2. 1. 2. 3. 4. 5. A proton and an antiproton each with total energy of 700 GeV collide head-on. What is the total energy (particles + energy) released? • 1,400 GeV • zero • 700 GeV • 4,200 GeV • 2,800 GeV

3. 1. 2. 3. 4. 5. Which of the following particle reactions cannot occur? • {image} • {image} • {image} • {image} • {image}

4. 1. 2. 3. 4. 5. Which of the following reactions cannot occur? • {image} • {image} • {image} • {image} • {image}

5. 1. 2. 3. 4. 5. What is the minimum energy needed to produce a muon? • 280 MeV • 390 MeV • 106 MeV • 800 MeV • 600 MeV

6. 1. 2. 3. 4. All particles can be classified into _____ . • leptons and baryons • hadrons and mesons • leptons and quarks • leptons and hadrons

7. Particles composed of quarks are _____ . • photons • neutrinos • leptons • hadrons • W and Z bosons

8. 1. 2. 3. 4. 5. The law of conservation of baryon number is that the _____ . • total number of baryons and leptons is conserved • total number of baryons is conserved • (number of baryons) - (number of antibaryons) is conserved • (number of baryons) + (number of antibaryons) is conserved • total number of mesons is conserved

9. 1. 2. 3. 4. 5. Which of the following reactions violates conservation of strangeness? • {image} • {image} • {image} • {image} • {image}

10. 1. 2. 3. 4. 5. The following reaction can occur by the strong interaction: {image} If the quark composition of the {image} is {image} the {image} is {image} and the composition of the {image} is {image} find the quark composition of the {image} • {image} • {image} • {image} • {image} • {image}

11. 1. 2. 3. 4. 5. Which of the following decays violates conservation of lepton number? • {image} • {image} • {image} • {image} • {image}

12. 1. 2. 3. 4. 5. According to the Hubble law, where {image} lightyears, what is the velocity of recession of a quasar at a distance of 7 billion lightyears from Earth? • {image} • {image} • {image} • {image} • {image}

13. 1. 2. 3. 4. 5. Spectrographic analysis of light from a distant galaxy shows that the galaxy is receding from Earth at {image} Use Hubble's law with {image} lightyears to estimate the distance to the galaxy. • {image} lightyears • {image} lightyears • {image} lightyears • {image} lightyears • {image} lightyears

14. 1. 2. 3. 4. 5. The strong nuclear interaction has a range of approximately {image} It is thought that an elementary particle is exchanged between the protons and neutrons, leading to an attractive force. Utilize the uncertainty principle {image} to estimate the mass of the elementary particle if it moves at nearly the speed of light. • {image} a K meson • {image} a Z boson • {image} a muon • {image} an electron • {image} a pion

15. 1. 2. 3. 4. 5. The rest-energy of the {image} boson is 96 GeV. Using this information, find the maximum length of time a virtual {image} boson can exist, in accordance with the uncertainty principle {image} • {image} • {image} • {image} • {image} • {image}

16. 1. 2. 3. 4. 5. If a {image} meson at rest decays in {image} how far will a {image} meson moving at {image} travel through a bubble chamber? • 77 cm • 53 cm • 61 mm • 8.1 cm • 7.4 cm

17. 1. 2. 3. 4. The omega-minus particle decays {image} with the {image} and the {image} eventually decaying into stable baryon(s) and lepton(s). Utilizing conservation laws, which of the following is the correct accounting of the decay products? • {image} • {image} • {image} • {image}

18. 1. 2. 3. 4. 5. Which one of the following is not true of neutrinos? • They are leptons. • They have a spin. • They have a charge. • One type of neutrino may change into another type of neutrino. • They do not take part in strong nuclear interactions.

19. 1. 2. 3. 4. 5. The attractive force between protons and neutrons in the nucleus is brought about by the exchange of a virtual pi-meson {image} Estimate the longest time a virtual {image} can exist, in accordance with the uncertainty principle {image} • {image} • {image} • {image} • {image} • {image}

20. 1. 2. 3. 4. 5. A model for how repulsive forces between two particles can be mediated by a third particle would be _____ . • two people in two skateboards each trying to grab the ball out of the other's hands • a person on a skateboard pushing against a wall • two skaters giving each other a shove • two skaters throwing a ball back and forth • two people in two canoes each trying to grab the ball out of the other's hands

21. In this course we have seen that baryons have inertial and gravitational mass, intrinsic angular momentum, and other internal properties that have been given names like baryon number, strangeness, charm, etc. The Standard Model's explanation for these properties of baryons is that _____ . • photons are states of something more elementary that can exist in multiple quantum states • according to the Heisenberg Uncertainty Principle quantum numbers are indeterminate • the leptons are states of something more elementary that can exist in multiple quantum states • quarks are states of something more elementary that can exist in multiple quantum states • the baryons are states of something more elementary that can exist in multiple quantum states

22. 1. 2. 3. 4. 5. The red shift of a quasar indicates that it is moving radially away from the Earth at a speed of {image} What is the age of the universe if we assume that this quasar has moved at the same speed relative to Earth since the Big Bang? {image} • {image} • {image} • {image} • {image} • {image}

23. 1. 2. 3. 4. 5. What is the acceleration (or deceleration) of the expansion of the universe determined by? • the dark matter in the universe • the dark energy in the universe • the standard matter, baryons and leptons • all of the above • only a and c above

24. 1. 2. 3. 4. 5. According to string theory, six space-time dimensions cannot be measured except as quantum numbers of internal particle properties because they are curled up in size of the order of _____ . • {image} • {image} • {image} • {image} • {image}

25. 1. 2. 3. 4. 5. Name at least one conservation law that prevents each of the following reactions. a) {image} b) {image} • a) charge, b) baryon number • a) baryon number, b) baryon number • a) charge, b) lepton number • a) lepton number, b) charge • a) baryon number, b) charge

26. Given the identification of the particles in Figure (b), what is the direction of the external magnetic field in Figure (a)? {image} • Into the page. • Out of the page. • Impossible to determine.

27. Consider the following decay: {image} What conservation laws are violated by this decay? • Energy. • Electric charge. • Baryon number. • Angular momentum. • No conservation laws.

28. Doubly charged baryons, such as the {image} are known to exist. Doubly charged mesons also exist. • True • False

29. 1. 2. 3. 4. 6. 5. Occasionally, high-energy {image} -leptons collide with muons and produce two neutrinos according to the reaction {image} . What kind of neutrinos are these? • {image} and {image} • {image} and {image} • {image} and {image} • {image} and {image} • {image} and {image} • {image} and {image}

30. 1. 2. 3. 4. 5. One of the mediators of the weak interaction is the {image} boson, whose mass is {image} . Use this information to find the order of magnitude of the range of the weak interaction. • {image} • {image} • {image} • {image} • {image}

31. 1. 2. 3. 4. 5. 6. Calculate the range of the force that might be produced by the virtual exchange of a {image} meson. • {image} • {image} • {image} • {image} • {image} • {image}

32. 1. 2. 3. 4. 5. When a high-energy {image} meson traveling near the speed of light collides with a nucleus, it travels an average distance of {image} before interacting. From this information, find the order of magnitude of the time interval for the strong interaction to occur. • {image} • {image} • {image} • {image} • {image}

33. 1. 2. 3. 4. 5. Identify the unknown particle on the right side of the following reaction. {image} • {image} • {image} • {image} • {image} • {image}

34. 1. 2. 3. 4. 5. The first of the following two reactions may occur, but the second cannot. Which conservation law does the second reaction violate? {image} {image} • {image} • strangeness • charge • {image} • baryon number

35. 1. 2. 3. 4. 5. A {image} particle traveling through matter strikes a proton. A {image} and a gamma ray emerge, as well as a third particle. Use the quark model of each to determine the identity of the third particle. • {image} • {image} • {image} • {image} • {image}

36. 1. 2. 3. 4. 5. Review problem. Supernova Shelton 1987A, located about 170,000 ly from the Earth, is estimated to have emitted a burst of neutrinos carrying energy {image} (see the figure). Suppose the average neutrino energy was 6 MeV and your body presented cross-sectional area {image} To an order of magnitude, how many of these neutrinos passed through you? {image} • {image} • {image} • {image} • {image} • {image}

37. 1. 2. 3. 5. 4. The energy flux carried by neutrinos from the Sun is estimated to be on the order of {image} at Earth's surface. Estimate the fractional mass loss of the Sun over {image} due to the emission of neutrinos. (The mass of the Sun is {image} The Earth - Sun distance is {image} ) • {image} • {image} • {image} • {image} • {image}

38. 1. 2. 3. 4. 5. Two {image} particles approach each other head on, each with 68.3 MeV of kinetic energy, and engage in a reaction in which a {image} and negative pion emerge at rest. What third particle, obviously uncharged and therefore difficult to detect, must have been created? • {image} • {image} • {image} • {image} • {image}