# Tag Info

8

Playing a vinyl "LP" implies a 33 rpm motion and 30 cm diameter. The highest frequency recorded will depend on the track velocity and the size of the needle. 30 cm diameter implies a 100 cm track length (roughly - less as you move further in) traversed in about 2 seconds - or 50 cm / second. The radius of the needle is specified in the standard as less than ...

7

Wikipedia states that The high frequency response of vinyl depends on the cartridge. CD4 records contained frequencies up to 50 kHz, while some high-end turntable cartridges have frequency responses of 120 kHz while having flat frequency response over the audible band (e.g. 20 Hz to 15 kHz +/-0.3 dB).[5] In addition, frequencies of up to 122 kHz have ...

7

The answer lies in the band structure of the two materials. The band structure describes how the electrons in a solid are bound, and what other energy states are available to them. Very simply, the band gap for transparent diamonds is very wide (see this link): Normally, diamond is not a conductor: all the electrons live in the "valence band", and you ...

4

Just a coincidence. There are too many quantities and not enough letters. It probably does make a difference that the fields in which these two equations exist (material science and electromagnetism) are well enough separated that you typically won't see them both in the same papers or textbooks; if that weren't the case, people would start using different ...

2

Yeah, that's just a coincidence. The easy way to see this is that $\epsilon$ is a relatively static property of a dielectric but a totally dynamic property of a stretching material.

2

Engineers created that problem. ;) (probably not) Many physics books use $Y$ for Young's modulus (Symon, Knight, Young & Freedman). Taylor's Classical Mechanics uses YM. Halliday, Resnick & -fill-in-the-blank- state that engineers use $E$. I suspect that physicists started using $Y$ for exactly this reason: to highlight a difference in the meanings ...

2

To construct a crystal you need a lattice and a basis. The lattice represents the translational symmetry of the system. Namely, graphene has a hexagonal lattice, meaning the two lattice vectors are 60 degress apart. Since the brillouin zone is constructed by inverting the lattice vectors, the brillouin zone is shaped based upon the lattice, but not the ...

2

The nuclear force is a contact force, with potential energy curve $$V \propto \frac{e^{-r/r_0}}{r}.$$ The range parameter $r_0$ is roughly one femtometer. Nuclei in a solid are typically $10^5\rm\,fm$ apart, so the nuclear interaction between nuclei from different atoms is astoundingly suppressed. If you think of a solid as a lattice of atoms connected ...

2

Facts : The properties depending of the atomic mass are different. fact 1 : The melting point depend upon the atomic mass. There is no need of a new experiment to relate the hardness to the temperature distance to the melting point : ie heat helps to bend metals or makes other matters more brittle. fact 2 : Moreover, stress diffusion depends upon the ...

1

Consider that the only frequencies present on the disk are spatial frequencies. The spatial information only gets transformed into the temporal domain when you spin the disk, and the scaling depends entirely on how fast you spin it. How fast can you rotate the disk? If a disk that nominally rotates at $33 \frac{1}{3}$ rpm is able to represent frequencies ...

1

There is one small effect that has not yet been covered in the other answers. When we solve Schrodinger's equation for the electron orbitals we use the so called reduced mass $$\mu=m_e m_n/(m_e+m_n)$$ so the solutions for the orbitals will be slightly different for the case where extra neutrons are added to the nucleus. The electron mass is so much smaller ...

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