Recent content by SongDog

  1. SongDog

    Have pulsed fission reactors got any potential in nuclear energy?

    Well, theres always Project Orion, but we can forget about using it near Earth.
  2. SongDog

    Is this much difference in data speeds between 2.4 GHz and 5 GHz WiFi bands normal?

    Odd that nobody asked what type of modem/router the OP was using. If, like most, it provides port(s) for wired LAN connection, the simple solution is to connect your own modern WiFi router there. You are then free to configure it whatever way you wish, irrespective of the ISP’s arbitrary bad...
  3. SongDog

    I Does the Skin Effect cause charge to accumulate on the surface of a conductor?

    Trying or not, if you have an alternating surface current you will transmit EM waves. It is inescapable when any charge undergoes acceleration (at least in classical EM theory). To calculate a capacitance you must specify the two conductive objects involved and the dielectric between them.
  4. SongDog

    I Does the Skin Effect cause charge to accumulate on the surface of a conductor?

    Please don’t presume everyone here is male, gentile, or anything else.
  5. SongDog

    B How far do photons travel inside common lasers?

    Or as low as zero. With sufficiently high gain, a pulse can be created in a single pass through the gain channel: no mirror required. Of course that pulse is not tunable, highly directional, nor long duration, but it is possible.
  6. SongDog

    COVID From 60 Minutes an Epidemiological View Of What Vaccination Level Is Needed

    Influenzas circulate and mutate in many wild and domesticated specie, not just humans. As a result, new variants arise frequently in swine, birds, even camels. AFAIK, we don’t yet see a similar behaviour for coronaviruses.
  7. SongDog

    Floating a cruise ship in a bucket of water

    It will if you do it right. Capacitance can be measured to exquisite sensitivity by counting individual electrons with a SQUID (vide Rod Harris-Lowe).
  8. SongDog

    B Exploiting radiocarbon dating for FTL communication

    Well, there's only one observer, the terrestrial one. In the observed frame, the distant Starshot sample should age slower. Consider a simple binary message: If life is detected, measure the first half of memory. Otherwise measure the second half. In the terrestrial wafer, does the remote...
  9. SongDog

    B Exploiting radiocarbon dating for FTL communication

    [Mentors' note: This thread was split from https://www.physicsforums.com/threads/can-we-carbon-date-a-gas.981218/] Empirical test: If one wished to implement a controlled experiment of this sort, start with separating stocks of pure C12 and pure C14 with a mass spectrometer. Use the C12 to...
  10. SongDog

    B Long term sustainable energy bounds

    "Is there an upper bound on the amount of sustainable energy/unit time that could ever be made useful to mankind?" That depends. Are you assuming it must be used on Earth? If so, we can start by considering how much sunlight intersects our disc. Earth has a polar circumference of about 4E7...
  11. SongDog

    B Why does GPS require an accurate clock?

    Have a look at https://en.wikipedia.org/wiki/GPS_signals and you'll see that rapid signal acquisition depends on having the receiver's clock within approx. 1.023 microsecond of the clock used for the received signal. A 32ns/day drift, over a month, would exceed that. Equivalently, so would an...
  12. SongDog

    Has anyone ever dealt with limescale in a bathroom sink?

    The process described by @Mark Harder is now done automagically in modern water conditioners. Once a month or so you dump a 20kg or 40kg sack of conditioner salt into a holding tank, and software does the rest. When brine is needed, water fills the holding tank long enough to saturate with NaCl...
  13. SongDog

    Are charged batteries heavier?

    @CWatters, you might want to re-read that Wikipedia entry more closely.
  14. SongDog

    Why doesn't a magnetically levitating conductor oscillate?

    In the DC limit, Lenz' law tells us that the EMF goes to zero. At nonzero frequencies the induced EMF is proportional to (and opposing) the rate of flux change, so lower frequencies would require higher currents to maintain the same peak lifting force. However, with ordinary...
  15. SongDog

    Do carriers move across a p-n junction at 0 K?

    Ask instead how the behavior changes as the carrier kinetic energy approaches zero: what is the limiting case?
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