Recent content by NewtonApple

What are the differences between 3d Nano-materials and bulk materials?

Homework Statement To show [J2, J+] = 0 2. Homework Equations J+ = Jx + i Jy [J2, Jx ] = 0 [J2, Jy ] = 0The Attempt at a Solution Step 1: L.H.S. = [J2, J+] Step 2: L.H.S. = [J2, Jx + i Jy ] Step 3: L.H.S. = [J2, Jx ] + i [J2, Jy ] Step 4: L.H.S. = 0 + 0 Step...

I read in a book "Optoelectronic Integration: Physics, Technology and Applications" edited by Osamu Wada. Ballistic Conduction and Superconductivity are both electron transport that are not affected by the collisions and scatterings. Ballistic conduction or Ballistic transport occurs when the...

thx! I'm re-posting it at Solid State forum.

I think it's a wrong forum. I'm re posting it at another forum.

Ballistic conduction occurs when the length of the conductor is smaller than the mean free path of the electron. Ballistic conduction differs from superconductivity due to the absence of the Meissner effect in the material. A ballistic conductor would stop conducting if the driving force is...

Ok I think I figure it out. lets take derivative one term at a time using product rule \frac{1}{r^{2}}\frac{\partial}{\partial r}\left[r^{2}e^{-\alpha r}\frac{\partial}{\partial r}\left(\frac{1}{r}\right)\right]=\frac{1}{r^{2}}\left[2re^{-\alpha r}\frac{\partial}{\partial...

Homework Statement [/B] The time-averaged potential of a neutral hydrogen atom is given by where q is the magnitude of the electronic charge, and being the Bohr radius. Find the distribution of charge( both continuous and discrete) that will give this potential and interpret your result...

Thx Vela! I'll give it another try. There is a misprint in the problem statement. I think (c) part should be \overrightarrow{r}.(\nabla.\overrightarrow{r)}\neq\left(r\nabla\right)r Are you OK with it?

Homework Statement [/B] Solving part (c) which should be \overrightarrow{r}.(\nabla.\overrightarrow{r)}\neq\left(r\nabla\right)r 2. Homework Equations Let \nabla=\hat{i}\frac{\partial}{\partial x}+\hat{j}\frac{\partial}{\partial y}+\hat{k}\frac{\partial}{\partial z} and...

Solving part (c). As suggested above it's also a misprint. It should be \overrightarrow{r}.\left(\nabla.\overrightarrow{r}\right)\neq\left(r\nabla\right)r

^ solve it

Yes, but we've to it in both - Cartesian and Spherical coordinates.

Ok, thanks for the input. Homework Statement Show that \nabla^{2}\left(\frac{1}{r}\right)=0 Homework Equations Let \nabla=\hat{i}\frac{\partial}{\partial x}+\hat{j}\frac{\partial}{\partial y}+\hat{k}\frac{\partial}{\partial z} and \overrightarrow{r}=x\hat{i}+y\hat{j}+z\hat{k}, \mid...

Dear BvU, I think Author referred it as a vector. In the book (Mathematical Methods for Physicists by Tai L. Chow) scalars are mentioned as non bold, such as in same exercise page other problems are