5. Which of the four interactions (strong, electromagnetic, weak, gravitational) does the electron take part in? The neutrino? The proton? 6. Quarks have spin 1/2. How do you account for the fact that baryons have spin 1/2 or 3/2, and mesons have spin 0 or 1?

Match these particle physics descriptions   A class of particles that consist of two quarks   An electron is a member of this class of particles.   A proton is a member of this class of particles   A class of particles that experiences the weak but not the strong nuclear force.   A class of particles that consist of three quarks   A class of particles that experiences strong and weak nuclear forces. 1. Hadrons 2.Mesons 3.Baryons 4.Leptons

Referring to the Feynman diagram, name:a. particle A b. the exchange particle involved c. the force involved in the interaction d. Explain how you know that there has not been a change of quark colour but there has been a change of flavour.

12. What is the wavelength of the photons produced in electron-positron pair annihilation?