# Tag Info

### Wien's displacement law

Stars are not perfect blackbodies. They have elements in their atmosphere that absorb and emit light at particular wavelengths. So the general blackbody pattern is slightly modified with lines of ...
• 41.9k

### Physical basis of "forced harmonics" on a violin

Some thoughts: The specification for the left hand: 'light pressure on the string'. Is that violonist jargon? That is: in this context, in what way is 'light pressure' different from 'normal pressure'?...
• 22.1k

### Can refraction change a wave's frequency?

No, refraction does not change the frequency. You can understand why the frequency must remain constant by considering the fact that the waves at the boundary must be continuous. If the frequency on ...
• 2,302

### Semiconductors and LEDs

Why the led is emitting a finite bandwith light centred at red wavelength even though it has "only one band gap"? IMHO, it is not quite clear what exactly the OP finds suprising here: that ...
• 61.8k
1 vote

### Vibrating string: why exactly these harmonics?

The string divides itself in this way because the endpoints are fixed, they cannot move. These are the boundary conditions of the problem. Say you divided the string into $3/4$ and $1/4$. That means ...
• 2,367
1 vote

### Vibrating string: why exactly these harmonics?

Trying to explain this at the same level as the excerpt you've provided: Think about a junction point where two portions of the string meet. It's constantly "feeling" the influence of each ...
• 50.4k
1 vote

### Can refraction change a wave's frequency?

The wave source controls the frequency. Different media change wave speed and wavelength, but the frequency remains constant per the equation $\frac{v}{λ}=f$.
• 12.3k
1 vote

### Can refraction change a wave's frequency?

There's very little to go on here, even after reading the complete transcript, because Nye wasn't given very much time to explain himself. But I'll try to interpret his comments as best I can: if you ...
• 28.7k

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