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Physicists - A Few Issues to be Addressed

  1. Dec 31, 2011 #1
    What is the fundamental knowledge that the average, or above-average physicist must possess? Put simply, even a subject as rudimentary as undergraduate level classical mechanics teems with so many formulae and so many derivations that I find it incredibly mind-boggling that a physicist should remember all of these details at all. Can someone kindly enlighten me on these processes:

    1) Taking an examination tested on a certain subject(s) in the undergraduate and graduate level; to ace the written examination with excellent scores (we exclude any formal assessment of experimental techniques for a moment), must one actually oblige himself to remember everything that is to be tested? In fact, I think I have a better question: WHAT is being tested on such written examinations at all? Do questions on the examination assume similar forms to textbooks written on the same subject?

    2) I extend this perplexity of mine to real-time physics careers. Is there some form of knowledge that physicists (it will be fantastic if anyone can relate to specific examples of a theoretical physicist's job - the one who investigates such things as quantum gravity and modern cosmology) must possess at all?

    3) Generally speaking, how much does a theoretical physicist working in the academia earn per annum? How much does the average physicist earn per annum?

    I apologize if I defined some of these uncertainties quite ambiguously; I've had no formal encounter and no experience with such issues whatsoever.
  2. jcsd
  3. Dec 31, 2011 #2
    Exam questions for written exams typically are almost identical to the homework exercises that were given during the course. Exercise questions in textbooks may be a good guideline for what those questions look like. The idea is to give concrete problems like "calculate the quantity X" or "show that if X then Y" and let the students solve it. Oral exams (which may be uncommon in most countries) usually try to focus more on understanding, typically starting with a simple and rather open question (e.g.: "what kind of systems is thermodynamics concerned with?"), and then progressing depending on the answer that the student gave. Ideally, the idea there is to give the student the opportunity to demonstrate how much physics he/she has understood. Thesis defenses usually involve the student presenting his/her work in a talk, and possibly having to answer questions from the audience. Usually, questions being asked in this context are those that arise naturally from the work presented (e.g.: "you have tried method X. What would you expect would happen if you tried method Y").

    It may qualify as mandatory knowledge to know that you shouldn't stick a metal needle into an AC power socket. That's probably not what you intended to ask for, though.

    That depends on country and position. For Germany, the numbers are roughly 45k (25k) for a post-doc, 51k (29k) for a group leader, and more for a full professor (values given in Euros, numbers outside and inside parentheses are before and after tax and insurances, respectively, tax level assumed is unmarried, salary for a professor are not regulated and therefore I gave no value, there). PhD students are typically given between 50% and 75% of the post-doc salary.
    Last edited: Dec 31, 2011
  4. Jan 6, 2012 #3
    I'm speaking as a 3rd year undergraduate. Exams test -generally- for an understanding of and the ability to apply the material covered, depends on the person who authored the exam. Some exams may be variations of homework/in-class problems, others may be composed of problems that don't resemble anything solved in class or in the suggested textbook (many times in my experience, which is why you need to be cunning and check other books while preparing for an exam), which you have to solve on the spot by applying what you've learned in theory (doesn't always work out). About 20-30% of my exam grades involve a theory question or two, where you have to do some short proof (ie: derive the law of conservation of charge from Maxwell's equations).

    I don't think classical mechanics has all that many formulas. If you know and understand a few basic relations and can handle geometry & calculus reasonably well, there's really no problem you can't set up the equations of motion for, generally speaking (I'm sure someone can come up with something impossibly hard though).

    I think most people will agree its not about knowing a ton of formulas, its about understanding them and being able to derive them from some general principle when necessary, then applying them properly to a given problem.
    Last edited: Jan 6, 2012
  5. Jan 6, 2012 #4
    Physicists learn techniques to manipulate equations. You don't need to remember every single equation. Electricity and magnetism boils down to Maxwell's equations and manipulations of them. Classical mechanics is Newton's laws, etc.

    Physics is about problem solving- you shouldn't expect to see the same forms on the written exam as you see in the textbook. A good test will have many problems that do follow textbook formats, and then a few that require you to stretch.

    The backbone of modern theoretical physics is quantum field theory. You'll need to learn it and love it- which requires deep knowledge of quantum mechanics and classical field theories, as well as a heavy dose of mathematics.

    So one thing to understand about physics is that the median career is very short. Most scientific careers won't last more than 4 or 5 years after a phd (one or two postdocs). That means the median physicist is probably a postdoc, and making 45k or so.

    As a phd student, you can expect to earn in the 20-25k range. A phd takes 5-7 years or so.

    After that, generally you do a postdoc which is a 2 or 3 year contract position. The average postdoc probably makes about 45k, but theorists make less (maybe 35k). You'll have to do one or two of these before you have a shot at the academic position lottery.

    If you win the academic position lottery (maybe 1/5 or 1/10 of the postdocs get permanent positions), you can expect to move up in salary in stages as you move towards tenure (a 7 year or so process). The median salary for full professors is probably around 90k, but the spread is quite large. Of course, if you don't get tenure, you're essentially fired.
  6. Jan 7, 2012 #5
    Only for experimental physicists. Wives and colleagues should keep theoreticians well away from power sockets :)
  7. Jan 7, 2012 #6
    :rofl: I almost spilled my coffee over this!
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