Recent content by pt176900

Problem 9.22 from Griffiths: Show that in deep water (where the depth is greater than the wavelength) the wave velocity is twice that of the group velocity. where Vw = w/k and Vg = dw/dk where w is the angular frequency, and k is the wave number. I'm really not certain how to proceed...

For non conducting materials, resistance would decrease with temperature. Heat is, more or less, agitation of molecules in a substance. If the temperature is great enough, electrons can be ripped from the atoms, thus allowing a current to flow.

I'm sorry but I don't understand what you mean by the independence of e^ix and e^x.

ok so wait... I can use x = 0 to prove A+B=C (I did it by contradiction ie assume A+B != C for all x. then insert x=0 and you get A+B=C - a contradiction). then can I use the fact that A+B = C to prove that a=b=c?

if I make x = 0 then the relation a=b=c need not hold. By this I mean that e^n*0 = 1 for all n, hence a, b, and c can be any real number. So basically I'd trade proving a=b=c for A+B=C

from Griffith's, problem 9.15: Suppose Ae^iax + Be^ibx = Ce^icx, for some nonzero constants A, B, C, a, b, c, and for all x. Prove that a = b = c and A + B = C I'm definitely confused on where to begin my manipulation. It seems quite reasonable to meet that the constants should be equal, and...

What are the boundary conditions for an electromagnetic wave?

From Griffiths: Problem 9.4 Obtain Eq. 9.20 directly from the wave equation, by separation of variables. Eq. 9.20: f(z,t)~ = integral [-inf, inf] A~(k)e^i(kz-wt) dk where ~ denotes the complex conjugate the wave equation: f''(z) = (1/v^2) f''(t) I'm a little confused on how I can...

interesting point... but won't I have to take a qualifying examination, regardless of where i end up going for a phd? to that end, wouldn't it be beneficial to take the requisite classes. It may be boring to take the material twice, but that could only help in the long run, right? to that...

I'm applying for an ms in physics, and I would like some input on choosing which option. The no thesis option requires 45 credits of work, including 7 required classes. The thesis option requires a written thesis, oral defense and 20 hours of graduate level work. With the intention of...

To monique, no, investing in an index fund wouldn't lose all your money unless the value of the index fund dropped to zero. in that case, you may assume the apocalypse is upon us. In other words, the price of a stock is a measure of investor perception regarding future cash flows of the...

How to invest your $1,000 all depends on you... what sort of investment horizon are you looking at? You could put the $1,000 into an index fund (the djia, s&p, nasdaq, etc) and leave it there for several years. This is *almost* a sure way of making money, as in general the markets tend to...

from first hand experience, they really don't do all that much. Specifically, I've used ritalin - my roommate has a prescription. really all it does is keep you awake and leave you feeling strung out. therefore, i'd put it on worthless borderline dangerous

What is the typical department's policy regarding allowing their graduate students to take classes not directly related to their field of study? for instance, If I were to become a graduate student in physics, would I be permitted to take undergraduate courses in fields such as mechanical or...

by erraticimpulse: "But the Bible has made definite and clear statements concerning the natural world. And still it remains uncontradicted or disproven." Ok, so you're saying that modern science doesn't contradict the notion that all of humanity could have developed from two people, ie Adam...