Recent content by tuomas22

nope that's all I have :( but this is an introductory course, so maybe I am supposed to make some assumptions? I don't know... lets assume it's isotropic

one last cry for help. then i quit :) exam tomorrow :(

Thanks for answer. But I still didnt get it. There was some strange matrices in those links, and we haven't talked about those in the class, so I don't think that's what I'm supposed to use. I also didnt understand the indices. For example if I have i=2 and j=1 for C21, what does it exactly mean?

could use some help :( please

any other opinions? I'm afraid of the upcoming exam, if this question is in it, I know I only get half the points because it happened with homework too...

any help? :smile:

Homework Statement Longnitudal and transverse soundwaves in nickel (FCC lattice) moves at velocities 5300m/s 3800m/s. Determine the elastic constants Cijkl Homework Equations v =\sqrt{C_{ij}/\rho} The Attempt at a Solution I guess I can calculate Cij with that equation...but I...

Object-image relation: 1/s + 1/s' = 1/f where s = object distance s' = image distance f = focal length

Homework Statement http://xs.to/image-A876_4BAF6DF1.jpg alpha = 54.6 degrees I need to calculate phase difference between E(perpendicular) and E(parallel) polarization components. Homework Equations The Attempt at a Solution Problem is I don't know any relevant equations...

well there must be something wrong because I lost 3 points (out of 6) with my answer :D but I am with you, i don't understand either what I did wrong.

The image doesn't form exactly to the focal point, that's how it was explained. But i don't know how i can get the .9 addition to the 18mm

Homework Statement A digital camera has a 3x zoom lens whose focal length can be varied between 6-18mm. The lens is assumed to be thin. The image is formed on a CCD sensor whose diameter is 10mm. 1. How large an object can be captured with the camera if the object is at distance of 10m from...

any tip would be much appreciated, I got exam tomorrow and I want to understand this :P

Aaah I got it! 0 = 0 finally :) There was some silly mistake in the equation. The derivation is still inhumane to do with pen and paper though :) Thanks much gabbagabbahey!

aaah the bohr radius equation, didnt even think about it :) (and Z=1 ofcourse) the next part of the question was to prove that the given R(r) is the solution to the schrödinger equation with l=0, and I got it right now with that bohr radius tip you gave! :) - \frac{1}{2}...