3. What particle in a decay signals the electromagnetic interaction? 4. Why is it that the neutron decays via the weak interaction even though the neutron and one of it's decay products (the proton) are strongly interacting?

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

1) a) Name four fundamental forces name the exchange particle associated with each force. Explain what an exchange particle does.

5. Pion beams (*) are used to treat cancer in radiation therapy. The energy comes from the decay of the pions. Negative pions usually decay into a muon and a muon antineutrino. (a) (b) Write out the complete decay of a л into stable particles. How much energy is released from a complete decay? Assume the neutrino masses are negligible. (c) How many pions need to decay to give a dose of 50.0 Gy to 10.0 grams of tissue?