# All Questions

2 views

### What is the aperture in the hydraulic analogy of Ohm's law

I do not understand the Hydraulic analogy explained on wikipedea. I asked my Network analysis teacher for an explanation . He told me that cross-section area of a pipe represents its ...
7 views

### Fresnel distance and Geometrical limit

I read about the geometrical limit of wave theory. The source from where I read had a slightly different explanation to provide than here(The more rigorous answer is too complicated for me to ...
11 views

### Planck's distribution and Bose-Einstein distribution?

If the application of the Bose-Einstein distribution is in blackbody radiation, then what is Planck's distribution? Are they same? How did Planck know that he should use a Bose-Einstein distribution ...
8 views

### diffracton at the edges?

To understand the phenomenon of diffraction as an interference effects of several dipole oscillators (like in case of several symmetrical, not sawtooth, scratches in a diffraction grating), we ...
24 views

### Lorentz Transformations

I am trying to understand Lorentz Transformations in SR. I have some doubts. 1) In the derivation for Lorentz Transformations, why do we assume that Galilean Transformations hold true when an ...
16 views

### Estimating the number of atom/nuclei in a single quantum dot

I often read in introductions about quantum dots that depending on the fabrication method, a single dot contains about 100 - 100000 atoms. Assuming a self-assembled dot of lens or pyramid (cone) ...
20 views

### Observations in the cathode ray tube experiement

1.One of the observations I learned was that the glass tube begins to glow with a brilliant green light. Many websites I read through refer to a fluorescent material. However, as shown in the above ...
17 views

### Stellar Activity Cycle versus Metallicity

Our Sun exhibits sunspot max/mins on about a 11 year period. It's a G2 spectral class on the HR Diagram. We know that some stars exhibit "starspot" cycles of various intensities and periods. These ...
12 views

### Characteristic waves in a plasma

What does "characteristic wave" mean in the context of plasma waves? For example, when propagating parallel to the plasma magnetic field, the characteristic wave is circularly polarized. Does this ...
49 views

### Resistors in series vs parallel

I understand that for resistors in series we need to add R for each resistor to get the equivalent resistance, where R is resistance. I also understand the mathematical manipulations that show that ...
31 views

33 views

### What is more important in terms of damage in a car crash, momentum or kinetic energy?

Momentum is $mv$, kinetic energy is $1/2 mv^2$ and I have a car run into a brick wall, or maybe an egg thrown against a wall. On one hand you can think about the maximum force exerted on the car or ...
55 views

I always have trouble remembering the sign in factors like $\exp(\pm ik\cdot x)$ (I'll use mostly minus signature here) that arise in field theory. My mnemonic is to remember that the Schrodinger ...

15 30 50 per page