Critical Thinking Items
23.1 The Four Fundamental Forces
The gravitational force is considered a very weak force. Yet, it is strong enough to hold Earth in orbit around the Sun. Explain this apparent disparity.
- At the level of the Earth-to-Sun distance, gravity is the strongest acting force because neither the strong nor the weak nuclear force exists at this distance.
- At the level of the Earth-to-Sun distance, gravity is the strongest acting force because both the strong and the weak nuclear force is minimal at this distance.
True or False—Given that their carrier particles are massless, some may argue that the electromagnetic and gravitational forces should maintain the same value at all distances from their source. However, both forces decrease with distance at a rate of
- false
- true
23.2 Quarks
Why are mesons considered unstable?
- Mesons are composites of two antiparticles that quickly annihilate each other.
- Mesons are composites of two particles that quickly annihilate each other.
- Mesons are composites of a particle and antiparticle that quickly annihilate each other.
- Mesons are composites of two particles and one antiparticle that quickly annihilate each other.
Does antimatter have a negative mass?
- No, antimatter does not have a negative mass.
- Yes, antimatter does have a negative mass.
How were particle collisions used to provide evidence of the Higgs boson?
- Because some particles do not contain the Higgs boson, the collisions of such particles will cause their destruction.
- Because only the charged particles contain the Higgs boson, the collisions of such particles will cause their destruction and will expel the Higgs boson.
- Because all particles with mass contain the Higgs boson, the collisions of such particles will cause their destruction and will absorb the Higgs boson.
- Because all particles with mass contain the Higgs boson, the collisions of such particles will cause their destruction and will expel the Higgs boson.
Explain how the combination of a quark and antiquark can result in the creation of a hadron.
- The combination of a quark and antiquark can result in a particle with an integer charge and color of white, therefore satisfying the properties for a hadron.
- The combination of a quark and antiquark must result in a particle with a negative charge and color of white, therefore satisfying the properties for a hadron.
- The combination of a quark and antiquark can result in a particle with an integer charge and color that is not white, therefore satisfying the properties for a hadron.
- The combination of a quark and antiquark can result in particle with a fractional charge and color that is not white, therefore satisfying the properties for a hadron.
23.3 The Unification of Forces
If some unknown cause of the red shift, such as light becoming tired from traveling long distances through empty space, is discovered, what effect would there be on cosmology?
- The effect would be substantial, as the Big Bang is based on the idea that the red shift is evidence that galaxies are moving toward one another.
- The effect would be substantial, as the Big Bang is based on the idea that the red shift is evidence that the galaxies are moving away from one another.
- The effect would be substantial, as the Big Bang is based on the idea that the red shift is evidence that galaxies are neither moving away from nor moving toward one another.
- The effect would be substantial, as the Big Bang is based on the idea that the red shift is evidence that galaxies are sometimes moving away from and sometimes moving toward one another.