Recent content by Yroyathon

I'm not sure but possibly. I am more certain that Sqrt[N_v * N_c] is approximately N_c.

well, you were right about them being roughly the same answer. the prof changed the answers on us, so that my previous submission (where I just used T=100 and the effective mass of the n-carrier) that had been marked incorrect is now correct. thanks!

thank you. that was exactly what I needed. I'd seen something similar to this in my web searches, but with the differences in constant notation (epsilon vs. epsilon_0 vs. kappa vs, etc.) I was pretty confused as to what was in the formula. thanks!

ok, but how do i calculate N_v without information about m*_p? the effective mass of hole. you say slightly larger, but, how do I calculate it with what's given in the problem?

the result I'm getting is, n=5.10299*10^(-11), but it should be 5.5*10^(-11). it's off by a little bit, and I can't explain how. I have the answer for this textbook problem, but I have to figure out How to get it.

nickjer, I guess I'm not sure I understand. i've tried just using the above formula (for n, in terms of N_c and E_g) with T=100, and it doesn't work. I don't doubt the possible truth of what you wrote, but I'm not sure how it explains why just using T=100 does not yield the proper result.

hi folks, I've gotten most of this problem but for one part. I've learned quite a bit reading about the physics involved here on the web, but for all I've learned when I apply it, it doesn't work (ie give the right answer). So, I'm missing something. Homework Statement In silicon, E_g =...

hi folks, almost done my semester of physics. this problem has my goat, can't quite figure it out. Done web searches endlessly, but most of the links are pdf articles that I can't access. Homework Statement A donor electron moves in doped semiconductor, for which ε/ε0 = 17.9 and m* =...

icysoul, you give me a tiny bit of confidence I might finish this problem. but for one thing. when calculating the reduced mass M, M = (M_1 * M_2) / (M_1 + M_2). Using M_1=M_2=7*m_p, I get M=7*m_p=1.1704*10^(-26) kg. this is different than what you wrote, M=2.34328*10^(-26) kg. this would...

well, you were right about the atomic radius. What I calculated before from modifying hydrogen's radius, and what I found on the internet about the atomic radius for nitrogen, were totally different. so using the new correct atomic radius for nitrogen (56 pm), I get 0.00100192 eV, which is...

I'm not sure how to respond to your response, since the approach of using angular momentum isn't quite comprehensible to me. in the book, they say A is angular momentum, and it's defined in this context as A^2 = L * (L + 1) * h-bar^2. Well, I guess this is the numerator of my new equation for...

i made a mistake, and fixed it, but I'm still wrong. I totally thought I had this one. Little help here. Homework Statement What is the minimum (nonzero) rotational energy of the ¹⁴N_2 molecule? Homework Equations E_rot = L * (L + 1) * E_0 * (m_e) / (4*M) M = (M_1 + M_2) /...

turns out that both my concerns were valid. once I included the mass of the proton along with the electron, that led to the right answer. also, the prof/computer wanted an exact answer, so no rounding.

got it! thanks so much for your help!

ok, so I start with (deltax)/(delta p_x) > h/(2*Pi). deltax = 2 * given radius. so (delta p_x) > h/(2*Pi*2*r) . now I square both sides (delta p_x)^2 > h^2/(4*Pi^2*4*r^2) , then divide by twice the mass (delta p_x)^2 / (2*m) > h^2/(4*Pi^2*4*r^2*2*m) , and this left term is the KE KE >...