Recent content by tommw

Light is one part of the electromagnetic spectrum. It is called light for convenience and historical reason and to distinguish it from other parts of the spectrum. So in fact light is an electromagnetic wave. Or in the other way: An electromagnetic wave with a frequency of some tens or...

No there isn't. :-( In fact every textbook still may use its own definition. On the other hand that's not so bad, because it forces students to really think about the problems and not only learn formulae by heart. Actually there is a ISO-Norm for geometric optics which is mostly used by...

Yes, there are many "black-outs" spaced a whole multiple of the wavelength from each other - in both directions + and minus. (or in other words, n can of course be negative). The reason why you only see one maximum/minimum in some data or video is probably that the experimentalist did not...

As I still don't know your setup, I have no idea how many phase shifts you will introduce at what points. But you're right, assuming that we introduce the same number of phase flips (three in the most simple case) in every path, then d1=d2 leads to constructive interference. In this case we will...

lezrati is right. When it comes to sledging, friction makes all the difference. Or why do you think it is forbidden to make your bob sledge heavier in olympic competitions although it wouldn't change air resistance when placed inside the bob sledge. But apart from that you may also ask if...

..well, you could work out by hand that \cos{(30^{\circ})} = \frac{\sqrt{3}}{2} But that would require that you know what the cosine actually is. Anyway it always a good idea to know where the formulae you use actually come from when doing physics.

Do you have a calculator? Locate the 'cos'-button on it. Type '30', then press the 'cos' button! If the result comes out to something else than 0.866 verify that your calculator is in degree-mode (e.g. "DEG" instead of "RAD").

The cosine can never exceed 1, so you're right, the maximal work is 5m*100N if the force is applied colinear to the displacement. The cosine of any other angle than 90° is smaller than 1, thus the resultant work is smaller than 500 J.

If I understand your setup correctly, cancellation is observed when d1 = d2, right? Then you will also observe cancellation for every path-length-difference that equals a multiple of your laser wavelength λ: d1 = n*λ+d2 (with n = ...-2,-1,1,2,...) so depending on your laser you'll have none to...

1. Your hand will be crashed. 2. The 'dx' is not just some formal residual. Its in fact the difference between two adjusting nodes in the formal Rieman Integration. You definitely need it and you can even use it to calulate with it (e.g. when x itself is a function of some other variable)...

You can slow down light simply by putting it into a dispersive medium. Light in water is slower than in air. In a medium with refractive index n, the phase velocity vp is given by vp = c / n So if you find a transparent medium with a very high refractive index, you can in principle slow down...

What kind of exam is that? I wouldn't think that you can be expected to give an accurate estimate of an area underneath a curve without knowing anything else. So in the case you really only have a graphical representation of the dependency f(x), the best way would indeed be to use one of the...

Interesting thought.. Do you consider the points A and B to be inside the cavity as well? (By the way, I don't see any picture attached.) Any thoughts about how such a "device" would look like? Normally you'd use a Halfwaveplate to rotate polarization. This will, however, not work in your...

yes and that is, what typically happens in solid state lasers unless you use a mode-selective element. The gain curve has a maximum. The mode closest to that maximum will start lasing first. That is the threshold. You may want to read...

I would guess your boundary conditions should be y=0 at x=0 and y=0 at x=a, right? Then you can solve for b=-1/2 and determine the ratio c/a to equal cosh(-0.5). To get a or c, you'd need another boundary condition.