What are WIMPs?

1. Very small, low-mass stars
2. A candidate class of dark matter that only interacts with thegravitational force
3. Stable, massive, sub-atomic particles that interact with theweak & gravitational forces
4. Stable, massive, sub-atomic particles that interact with thestrong & gravitational forces E) A candidate class of darkmatter that only interacts with the electromagnetic force

[22] In beta-decay of a neutron into a proton….

1. A down quark decays into an up-quark emitting an electron andan anti-neutrino
2. An up quark decays into a down quark emitting a positron and aneutrino
3. A down quark decays into an up-quark emitting an positron and aneutrino
4. A down quark decays into an up quark emitting a photon
5. A down quark decays into a top quark emitting an electron andan anti-neutrino

[23] What is the main energy generationmechanism in stars on the main-sequence?

1. Nuclear fision of hydrogen into helium
2. Nuclear fusion of hydrogen into helium
3. Release of gravitational potential energy as the starcontracts
4. Collapse of the stellar core into a neutron star or blackhole
5. Nuclear fusion of helium into heavier elements

[24] Pulsars are:

1. Accreting black holes
2. Spinning white dwarf stars
3. Spinning neutron stars
4. Pulsating neutron stars
5. Spinning giant stars

[25] Which particles likely “froze out”earliest in the history of the universe?

1. Neutrons
2. Quarks
3. Photons
4. WIMPS
5. Electrons