Recent content by scoobmx
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Graduate Antisymmetric gradient matrix?
Does this operator (in 3D): ε_{ijk}∇_k = \begin{pmatrix} 0 & \frac{\partial}{\partial z} & -\frac{\partial}{\partial y}\\ -\frac{\partial}{\partial z} & 0 & \frac{\partial}{\partial x}\\ \frac{\partial}{\partial y} & -\frac{\partial}{\partial x} & 0 \end{pmatrix} have a formal name and a more...- scoobmx
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- Gradient Matrix
- Replies: 1
- Forum: Differential Geometry
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Graduate Can a Photon be Vibrationally Tuned with Sound?
http://en.wikipedia.org/wiki/Acousto-optic_modulator- scoobmx
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- Forum: Quantum Physics
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How Does Electron Flow Correspond to Electric Field Direction in Circuits?
Electrons are negatively charged and so move against electric field lines naturally. It's the opposite of the positive test charge.- scoobmx
- Post #6
- Forum: Introductory Physics Homework Help
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How Does Electron Flow Correspond to Electric Field Direction in Circuits?
Electrons moving from -ve to +ve are not moving against the field. They are negatively charged and so are moving with the field.- scoobmx
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- Forum: Introductory Physics Homework Help
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Determining the mass of Pluto using its moon
I don't think the size of the orbit is the only factor. The period also has to be in there somewhere I believe.- scoobmx
- Post #4
- Forum: Introductory Physics Homework Help
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Graduate Why don't we see quantum weirdness in everyday world?
http://en.wikipedia.org/wiki/Quantum_decoherence- scoobmx
- Post #3
- Forum: Quantum Physics
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Graduate TE Waves in Rectangular Wave Guide
Only the normal component is continuous.. so B is parallel to surface at the boundary.- scoobmx
- Post #7
- Forum: Electromagnetism
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Graduate Photon Amplitude: Is It Right or Wrong?
The AMOUNT of photons relates to the intensity. The amplitude gets normalized so that the probability of finding it somewhere is 1. So the amplitude itself means nothing but its phase and distribution does.- scoobmx
- Post #6
- Forum: Quantum Physics
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Undergrad Is the derivative of a vector perpendicular always?
The physical principle is the acceleration is toward the gravitation body, which if you place at the origin means it accelerates everything around it straight toward itself, which is the radius direction. -
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Potential outside charged metal sphere.
Ah, my mistake, I just read the problem again to find it's a metal sphere. You're going to want to add a dipole-like term into the superposition solution. This is because a metal sphere screening a uniform external field will move its surface charge to produce dipole-like fields. The...- scoobmx
- Post #8
- Forum: Advanced Physics Homework Help
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Undergrad Zero Momentum in Elastic Collisions
The vector has implied dimensionality. Zero scalar means 0 in 1 dimension. Zero vector means 0 in all components of the vector. -
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Potential outside charged metal sphere.
Can you quote this 'general solution'? I suggested superposition because the external electric field doesn't affect the charge distribution of the sphere (at least I assumed it was all bound charges) so in the electric field point of view it's just the sum of the 2 parts. You do not need to...- scoobmx
- Post #5
- Forum: Advanced Physics Homework Help
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Undergrad Is it possible to move air using a magnetic field?
http://en.wikipedia.org/wiki/Magnetohydrodynamic_drive- scoobmx
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- Forum: Electromagnetism
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Graduate Why are Fe, Ni, Co ferromagnetic among metals?
It has to do with the density of states of the D band. The energy spacing between states is small enough that the cost of energy of moving some antiparallel electrons up to higher energy parallel states (because the lower energy states are already occupied) is met by the energy gained from...- scoobmx
- Post #2
- Forum: Atomic and Condensed Matter