REVIEW SHEET – Modern Physics
1.
Read Chapters 23 and 25
2.
Terms to know: photoelectric effect, photon, Planck’s constant, matter waves, de Broglie wavelength,
emission (bright-line) spectrum, absorption (dark-line) spectrum, Balmer series, energy level diagram,
ground state, ionization, excited state, nucleon, universal mass unit, fusion, fission, alpha particle,
Geiger-Marsden experiment, electron cloud model, Standard Model, hadron, lepton, positron, neutrino,
baryon, meson, antiparticle, quark, antimatter, force carriers, pair production, pair annihilation.
3.
Define:
a) threshold frequency
b) work function
c) binding energy
d) mass defect
4.
Briefly describe the photoelectric effect experiment.
5.
What does classical theory say about light?
6.
What does quantum theory say about light?
7.
What is a photon and what are some of its properties?
8.
Which color photon has the highest frequency? Wavelength? Energy?
9.
A light source shines on a piece of metal causing the ejection of photoelectrons. What will happen to
the number of electrons ejected and to the kinetic energy of the ejected electrons when the:
a)
frequency of the light increases?
b) intensity of the light increases?
10. Sketch a graph of the relationship between the energy of a photon and its
a)
frequency
b) wavelength
11. Be able to calculate the energy of a photon in both electronvolts and joules. What is the conversion
factor?
12. What is the formula for the:
a)
photoelectric effect?
b) work function?
13. Be able to analyze and draw graphs of the photoelectric effect. What is the significance of the:
a)
slope?
b) x-intercept?
c)
y-intercept?
14. When a photon collides with an electron,
a)
what changes occur to the photon?
b) what quantities are conserved?
c)
what property of the photon is demonstrated?
d) how is the momentum of the photon calculated?
15. Be able to calculate the de Broglie wavelength of particles. What formula is used?
16. Briefly explain what is meant by “wave-particle duality” or “the dual nature of matter and energy.”
17. What experiments/phenomena demonstrate the
a)
wave nature of light?
b)
particle nature of light?
c)
wave nature of matter?
18. As the speed of an electron increases, what happens to its wavelength? Frequency?
19. What is the fundamental source of all energy in the universe, according to Albert Einstein?
20. Give examples of the conversion of matter into energy and the conversion of energy into matter.
21. Be able to calculate the conversion of mass to energy and vice versa. What formula is used?
22. What are the two main observations and conclusions of the Geiger-Marsden experiment?
Observations:
a)
b)
Conclusions:
a)
b)
23. What are the two main postulates of the Bohr model of the atom?
a)
b)
24. What is the major limitation of the Bohr model of the atom?
25. Be able to read energy level diagrams for hydrogen and mercury and calculate the energy
released/absorbed during transitions, as well as the frequency and wavelength of the associated
photons.
26. What are two units for electric charge? Be able to convert between each.
27. What are two units for mass? Be able to convert between each.
28. What holds the nucleus together?
29. The mass of a stable atomic nucleus is less than the sum of the masses of the individual nucleons.
Why?
30. Be able to calculate the mass defect and the binding energy for a nucleus. What two formulas are
used?
31. According to the Standard Model, what are the three types of fundamental particles?
32. Be able to read the Standard Model and Classification of Matter charts.
33. What is the difference between a particle and its antiparticle?
34. What is the quark content of a:
a) proton?
b) neutron?
c) antiproton?
d) antineutron?
e) electron?(trick question!)
35. How many quarks make up:
a)
a baryon?
b) a meson?
c)
a lepton?
36. a) Name each of the four fundamental forces.
b) Which are long range and which are short range?
c) Which is the strongest? weakest?
d) Name the force carrier for each force.
38. What happens in:
a) pair production?
b) pair annihilation?
39. What is some experimental evidence that these strange “exotic” particles described by the Standard
Model exist?