History 181B: Modern Physics

Exam Review

This course has two examinations, a midterm and a final.

• The midterm (50 minutes, take-home, closed-book) can be picked up in class beginning Wednesday, October 12. It is due in class on Monday, October 17.
• The final (scheduled for 3 hours, closed-book) will be given Saturday, December 17 , from 5:00-8:00 p.m.

You have two options with respect to the exams:

• Midterm plus final option: The midterm counts for 2 parts in 10 of your course grade; the final, for 4 parts in 10.
• Final only option: Do reading responses. Skip the midterm and take a reduced version of the final. Then the final counts for 2 parts in 10 of your course grade; the reading responses, for 4 parts in 10.

Each exam covers all course material up through the lecture and reading assigments immediately preceding. The final exam is cumulative.

The midterm includes both short-answer and paragraph-answer questions. The final does as well. But students taking the reading response option do not have to do the short answers on the final; nor do they have to answer as many paragraph questions.

Sample exams are provided below. I reserve the right to change the format and number of questions.

Short-answer questions

These typically come directly from reading or lecture. If the latter, the list of names and terms is heavily emphasized. Worksheets may also be useful. Short-answer questions generally ask for a one-sentence identification of a person, organization, event, etc. Occasionally they require an additional brief comment on their place in the history of physics. Full sentences are not necessary if the answer does not demand them.

In most cases, either you know the answer or you don't. Strong answers demonstrate basic factual knowledge. Lots of details are not required. Weak answers are vague allusions to a topic or period, or else guesses based on science knowledge that get the history wrong.

Paragraph-answer questions

These call for more in-depth discussion of developments or themes in a coherent paragraph of six to nine sentences. Make sure you answer each part of the question.

Strong answers combine a well-argued response to the question with relevant evidence. They identify the question at stake and respond directly to it. They include enough detail (e.g., key words, names of major figures, time location if relevant by quarter-century or so) to demonstrate knowledge. Weak answers are brain-dumps of facts without an organizing principle, or grand assertions poorly supported by evidence. Writing down everything remotely related to a topic, but not answering the question, does not help you. It just makes it obvious that you are grasping for straws.

These questions sometimes ask you to paint a "big picture." To do this successfully, however, you also have to make your answers concrete; the bulk of the points for each question are allocated to examples and illutrations. Don't theorize without specific cases. When you introduce a specialist concept or technical term, take a half-sentence to make it plain that you know what it means. You can skip the grand "historical" flourishes ("Over the generations, physics progresses ...").

Some questions ask for more scientific knowledge, others for more history. You may pick questions that speak to your strengths, but you will not be able get away with knowing only science or only history.

Short-answer

25% of the grade, answer 4 of 7.

1. Who described the goal of physics as "to save the phenomena," and what did this mean?
2. What is kinematics?
3. What was the Tripos, and who were the wranglers?
4. What is the mechanical equivalent of heat, and who measured it?
5. What is our name for what Germans call Röntgen rays?
6. What law did Rudolf Clausius help formulate?
7. What is Brownian motion, and what theory explained it?

Paragraph-answer

75% of the grade, answer 3 of 6.

1. Recount the fate of the mechanical philosophy from its origins to the turn of the 20th century. Begin by describing the mechanical philosophy that emerged from Newton's works (note the plural). Then trace the ramifications of the doctrine through the 18th and 19th centuries and describe its status (including that of the mechanical world picture) in 1900.
2. Imagine a young woman from an Eastern European country who wanted to study physics in the 1890s. What were her options, and what difficulties did she face? If you like, you may answer the question by discussing a specific example.
3. Why weren't x-rays discovered before they were? That is, what preconditions (experimental or theoretical) were needed before they could be found? The more details you can give, the better your answer will be.
4. Explain the difference in levels of focus in thermodynamics on the one hand, statistical mechanics on the other: what different explanatory goals do these theories set for themselves? How is this difference significant for late 19th-century debates about the aim of science? You should lay out the issues in a general framework and then give one or two specific examples.
5. What sort of creature was the theoretical physicist of the late 19th century? What were his origins and his duties? Why did he emerge?
6. Many of the natural philosophers and physicists we have studied worked in several domains of physics at once (for instance, thermodynamics and electromagnetism). Pick out two figures and briefly explain (about 2 sentences each) what they contributed to their different fields. You need only give 2 domains per figure, though you may add more if you wish. What made their double mastery possible and productive? ("There was less to know back then" is not an adequate answer.)

Short-answer

"Midterm plus final" option: 25% of the grade, answer 8 of 14.
"Final only" option: skip.

1. What did the MIT Rad Lab work on, and when?
2. What was the Tripos, and who were the wranglers?
3. What did James Chadwick discover?
4. What is the mechanical equivalent of heat, and who measured it?
5. What is kinematics?
6. What is our name for what Germans call Röntgen rays?
7. What is the exclusion principle, and who devised it?
8. What law did Rudolf Clausius help formulate?
9. Who described the goal of physics as "to save the phenomena," and what did this mean?
10. What was the Federation of Atomic Scientists, and when did it flourish?
11. For what did Richard Feynman receive his Nobel Prize?
12. Which kind of atomic bomb needed testing before use? Name both the material and the design.
13. What is Brownian motion, and what theory explained it?
14. What is vacuum polarization, and why was it troubling in the 1930s and early 40s?

Paragraph-answer

"Midterm plus final" option: 75% of the grade, answer 6 of 11.
"Final only" option: 100% of the grade, answer 5 of 11.

1. Outline the sources of funding for physics from the mid-19th century through the present. What institutions or bodies are interested in supporting physics, and why? Identify what you see as the major turning points in this development and explain their causes.
2. Explain the difference in levels of focus in thermodynamics on the one hand, statistical mechanics on the other: what different explanatory goals do these theories set for themselves? How is this difference significant for late 19th-century debates about the aim of science? You should lay out the issues in a general framework and then give one or two specific examples.
3. Trace the history of the notion of the "field" from Faraday to the present. Don't forget the intermediate milestones of the late 19th and early 20th century. Is there an overall direction to this trend, or is it just a random walk? What would Faraday think about contemporary (QFT) notions of fields?
4. Many of the natural philosophers and physicists we have studied worked in several domains of physics at once (for instance, thermodynamics and electromagnetism). Pick out two figures and briefly explain (about 2 sentences each) what they contributed to their different fields. You need only give 2 domains per figure, though you may add more if you wish. What made their double mastery possible and productive? ("There was less to know back then" is not an adequate answer.)
5. Describe the conflict between the two forms of quantum theory (Heisenberg's and Schrödinger's) in the mid-1920s. What were the factors that make the conflict between these two mathematical formalisms so sharp? How did the conflict finally get resolved?
6. Imagine a young woman from an Eastern European country who wanted to study physics in the 1890s. What were her options, and what difficulties did she face? If you like, you may answer the question by discussing a specific example.
7. Describe the rise of physics at Berkeley from the late 1920s into the early 1950s. Who are the dominant figures on this development? What kind of physics gets done here, and how is that important for the rest of the American physics community?
8. Is the development of modern physics marked by revolutionary transitions or continuous development? Take two examples -- one from before the midterm and one from after -- and argue for your answer. Take into account both the impacts of the theories and the intentions of their creators.
9. What has happened to the notion of mass from Newton's era to the present? First describe the (more or less implicit) Newtonian concept of mass. Then explain how the concept was stretched in the theories of the late 19th and early 20th centuries. How have contemporary physicists' notions of mass taken leave of the Newtonian picture?
10. How did the idea of the quantization of energy find its way into physics, and how was it put to use in the first decade and a half after its appearance?
11. Recount the fate of the mechanical philosophy from its origins to the turn of the 20th century. Begin by describing the mechanical philosophy that emerged from Newton's works (note the plural). Then trace the ramifications of the doctrine through the 18th and 19th centuries and describe its status (including that of the mechanical world picture) in 1900.