# All Questions

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### Non-Linear Density Shell Problem

I'm trying to understand Newton's Shell Theorem (Third) http://en.wikipedia.org/wiki/Shell_theorem However this applies to a sphere of constant density. How is this formulated for sphere of varying ...
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### capacitance between widely-separated parallel plates

There's a caveat, which is often ignored, to the "easy" equation for parallel plate capacitors C = epsilon * A / d, namely that d must be much smaller than the dimensions of the parallel plate. Is ...
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### Is there a timeline in urban area night temperature?

Fact: We all know that during the day concrete absorbs heat and releases it during the night, making urban areas hotter than rural areas. I observed that after sunset the ambient temperature is going ...
257 views

### Changing the capacitance of an object to trigger a capacitive touchscreen [closed]

I'm trying to trigger a human touch in a capacitive touchscreen without the 'human' part. I've noticed that the negative pole of a battery triggers it if you are currently holding it. Or if you use ...
621 views

### Geometric/Visual Interpretation of Virasoro Algebra

I've been trying to gain some intuition about Virasoro Algebras, but have failed so far. The Mathematical Definition seems to be clear (as found in http://en.wikipedia.org/wiki/Virasoro_algebra). I ...
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### How is the complexification of spacetime justified?

As always the caveat is that I am a mathematician with very little knowledge of physics. I've started my quest for knowledge in this field, but am very very far from having a good grasp. General ...
179 views

### Magnification multiplication using telescope arrays?

If we have an array of telescopes attached one after another, would the resultant magnification be multiplied?Also would such a contraption be feasible to make telescopes with amazing magnification?
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### Does 'ring' diaphragm reduce lens spherical abberations?

As I see it, as light comes through approximately same angular area of the lens, it should have less aberrations, and at the same time, it should still have high θ -> diffraction limit should stay as ...
454 views

### Wave equations & propagation theories

I'm interrested in making computer simulation but I've run into rather physics oriented problem. I have to choose how to propagate my wave. Though I've found technique called FDTD (finite-difference ...