# Recent content by alexgmcm

1. ### The relationship between the lattice spacing and the distance between parallel planes

I found the solution had already been posted here: https://www.physicsforums.com/showthread.php?t=119037 Can someone explain why the sum of the squares of the cosines is equal to one though? It just says 'from trig' but I'm not familiar with that identity :/
2. ### The relationship between the lattice spacing and the distance between parallel planes

How can one derive the relationship for a cubic crystal: d= \frac{a}{\sqrt{h^2 + k^2 + l^2}} It is shown here. This is probably trivial but I am having trouble proving it as the Miller indices are reciprocals but the reciprocal is not distributive. This isn't for homework by the way - I...
3. ### Where can I find theoretical isochrones?

I found the data here http://stev.oapd.inaf.it/cgi-bin/cmd it is rather laborious to strip the data calculate the relevant colour index and plot it so I might make a python script to do it. I hope this will be of use to anyone else who has the same problem and comes across this thread via the...
4. ### Where can I find theoretical isochrones?

I am currently doing a 2nd year lab report and need some theoretical isochrones to work out the age of some clusters, M15 and H+chi persei (Double Cluster). I was going to use Seiss: http://www-astro.ulb.ac.be/~siess/server/iso.html [Broken] But it doesn't seem to be online :( What...
5. ### The treatment of errors and uncertainties?

Thank you!!! This finally made me understand that confusion I had. Now it all makes sense, I think so far in my experiments I am justified in assuming uncorrelated (i.e. independent errors) and so therefore need not worry about covariance.
6. ### The treatment of errors and uncertainties?

I am confused over how to work with errors and uncertainties. So far when dealing with a small number of measurements I have used the partial derivative method to calculate the final error in my result e.g. if my result is E=mgh \text{ then assuming no error in g my uncertainty is }...
7. ### Programs How easy is it to find funding to do an Applied Physics PhD abroad?

Those look interesting, I'll see what research is available at my university too as it'd be cool to get to know the staff well before third and fourth year where there is more research done (that's a horrible sentence but you see what I mean :P ) I'll try and apply for IAESTE too but that...
8. ### Programs How easy is it to find funding to do an Applied Physics PhD abroad?

I got a 1st (87%) in the First Year and am just entering the second, that got me on the Deans Commendation thingy which is like ~40 students out of each year or something. I also receive a scholarship from the university due to getting 5As at A level from a struggling school (if only they had...
9. ### Programs How easy is it to find funding to do an Applied Physics PhD abroad?

Although I am not yet sure which area I would want to do a PhD in (I am only in 2nd year undergrad) it would most likely be something applied like accelerator physics, plasma physics, metamaterials, plasmonics etc. (I realise this is a ridiculous range of topics :P ) The proposed ~30% cuts to...
10. ### Hey, guys and gals, it's vanity time!

Panda eyes, yay! Apparently as a male, I look like Edward Norton. As much as I wish that were the case, I don't really see it myself :P
11. ### Please explain what a Fourier transform is?

Hmm, I noticed that the period goes to infinity and thus the discrete summation becomes a continuous integral, but what does that actually mean? I mean what is it that the Fourier transform actually tells us, what is it used for? I understand the usefulness of being able to approximate functions...
12. ### Please explain what a Fourier transform is?

I understand Fourier Series fairly well and how to use them to approximate functions (I even wrote a C program to do it) but Transforms are really confusing. If I was to take the value of each fourier coefficient and plot it on the y-axis against the angular frequency on x-axis (obv. there...
13. ### Physics Making it as a physicist

Indeed, as Newton said "If I have seen further it is only by standing on the shoulders of giants." and was it E.O Wilson who said "Genius is the hard work of many attributed to the names of a few for convenience." Evolution or transmutation as it was known before, was understood to have...