A positron and an electron differ in
a. charge.
b. mass.
c. spin.
d. energy.
[Ques. 2] The Dirac theory predicted that a positron would be
a. a negative electron in a negative energy state.
b. a particle with same mass as an electron but with opposite charge.
c. a particle with negative mass.
d. All of the above.
[Ques. 3] The exchange of mediating photons can produce
a. neither a repulsive nor an attractive force.
b. either a repulsive or an attractive force.
c. a repulsive force.
d. an attractive force.
[Ques. 4] The strong force is mediated by
a. the gluon. b. the W boson.
c. the W+ boson. d. All of these choices.
[Ques. 5] Which of the following forces is the strongest at near distances?
a. gravitational b. weak nuclear
c. strong nuclear d. electromagnetic
[Ques. 6] Which, if any, is an elementary particle?
a. the proton
b. the particle
c. the muon
d. All three are not elementary particles.
[Ques. 7] If the lifetime of a particle is roughly inversely proportional to the relative strength of the force involved, then for the strong, electromagnetic, and weak forces, arrange the forces according to their resulting lifetimes ranging from shortest to longest lifetimes.
a. strong, electromagnetic, weak
b. weak, electromagnetic, strong
c. weak, strong, electromagnetic
d. strong, weak, electromagnetic
[Ques. 8] Theoretical physicists have had the greatest success in combining which force with the electromagnetic force?
a. strong nuclear force
b. weak nuclear force
c. gravitational force
d. the force caused by the exchange of gluons
[Ques. 9] Theoretical physicists have had the least success in combining which force with the electromagnetic force?
a. strong nuclear force
b. weak nuclear force
c. gravitational force
d. electrical Coulomb force
[Ques. 10] The weak force that acts between an electron and a quark is caused by the exchange of
a. photons.
b. gluons.
c. gravitons.
d. W+, W, or Z0 bosons.
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