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Sensei

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Everything posted by Sensei

  1. I have Android 5.0, so maybe it's version dependent.
  2. I have Samsung Galaxy S5. Assume you have Android (you didn't mention which version, every one is different) tablet. When I click on Applications > Settings, near bottom of the list, there is Internet icon. In Advanced, there is option "content settings" (don't know what it's called in English version of phone). Once you click it, there is "Default memory for writing". I have picked up "Device". Are you able to switch it to card.. ? I have built-in 16 GB, and didn't reach level of usage needing plugging card, but I guess so when there is card plugged, this option will change target for downloads..
  3. Are you aware of Hafele–Keating experiment? https://en.wikipedia.org/wiki/Hafele%E2%80%93Keating_experiment If they're both at rest, in same FoR, clocks are synchronized.
  4. You don't have fire.. ? If there is substantial amount of gas then place above it up side down beaker, filled with water first, so it'll be filled by gas going up. Then try to fire it. If there is explosion, it's Hydrogen, the most likely. In presence of not flamable gas, such as Carbon dioxide, fire will shut down. In presence of Oxygen, fire will start burning more intense. How about placing it in other liquid, that has no water.. ? If it's caused by reaction with water, there will be no gas, or reaction will be different. If it's what John said, gas bubbles will appear also.
  5. Special relativity is used all the time in quantum physics. During f.e. calculations of decays of unstable isotopes, calculation of particle collisions in particle accelerators in CERN etc. If you have high resistance, your current (and thus strength of created magnetic field) will be very small.. I=U/R for U=12 V, R = 100 ohm, I = 0.12 A, which means Q=0.12 C in second, which means 7.4898*10^17 electrons per second. Coils are typically made of Copper, because it has very small resistance! To be able to pass as large current as possible. To have as large magnetic field as possible. for U=12 V, R = 0.1 ohm, I = 120 A, which means Q=120 C in second, which means 7.4898*10^20 electrons per second. Scientists at CERN, while using superconducting electromagnets have to fight with what you described, as it can cause serious damage to devices. Once the main source of power is turned off, and coil is starting making its own current, there should be secondary circuit turned on, with elements that have high resistance, such as lightbulbs, or heating elements in water/oil, that will convert stored energy to photons in visible range, or heat, that will be easily to cool down.
  6. Hello! I see subject hypervelocity stars is not very common here. Just a few threads about it, years ago. So if you're not familiar with them please read first http://www.space.com/24432-hypervelocity-stars-ejected-from-milky-way.html http://www.space.com/8801-superfast-star-shot-milky.html Quote from article: "None of these hypervelocity stars come from the center, which implies there is an unexpected new class of hypervelocity star — one with a different ejection mechanism." I would like to share my hypothesis how this could happen (at least for some of them): Hypervelocity star (or two not joined together yet, but accelerated normal stars), ejected from center of galaxy, hit yet another star on their path, and joined together with it. Because of having to conserve momentum, it appears coming from different location than center of galaxy.. So precise analyze of path in the past of these stars will tell where they approximately hit something, using typical velocities at given radius from center of galaxy. Best Regards!
  7. You discredited yourself, before you even started explaining your experiment (that you're just mentioning).. So, I guess so, it's all "valid" as the rest of your claims.. I will give you something for consideration. Classically current I, voltage U, charge Q, are not quantized. But in oil drop experiment we were able to find out quantization of charge e = 1.602176565*10^-19 C. https://en.wikipedia.org/wiki/Oil_drop_experiment Equations for power P = I * U and for energy (simply power * time): E = I*t * U = Q * U Q is quantized in chunks 1e, 2e, 3e, ...., 10^18 e and so on. There can be 1 electron, 2 electrons, or billion electrons, but not half electron. Kinetic energy of single electron in wire in your radiowave emitting device: E.K. = 1e * U That's what electron could release at maximum upon acting with matter. Typically heating it. But can also emit visible light (like it happens in LED, lightbulb, laser). If source electrons in battery (or other source of electric power) flowing through wire, through your radiowave emitting element, were quantized, how come emitted by them photons won't be quantized either.. ? You are concentrating on detection of RF, instead of also looking at source of energy that you're using to producing your RF photons.
  8. Induction in non-metals? How do you explain bouncing off radiowave from walls in your room in that case? They're made of non-metals (or metals bound in compounds such as white paint Zinc Oxide or Titanium Oxide).
  9. You can/should do this experiment by yourself. PMT cost $30-$40 http://www.ebay.com/bhp/photomultiplier
  10. What is wrong with avalanche mode? Single photon, no matter if it's RF, visible, or x-ray, has very little energy, in comparison to everyday macroscopic scale.. So there is needed amplification. You could miss annihilation of matter with antimatter if you would use just your own eyes (or your devices). It's 400 millions times less energy than battery with U=5 V, I=25 mA, t=1s.
  11. Knowledge of somebody is increasing with time (unless he/she has Alzheimer or lost memory), so you could show relation f(x)=knowledge(time)=knowledge(time-1)+average knowledge gain per second*1s (if time is in seconds unit). Knowledge second ago is smaller than knowledge now. New data arrived to your brain by input devices such as eyes, ears, touch, smell etc. They were collected in your brain. Could remain there for seconds, hours, days, or years. Depending on importance, and their value, and whether you will be repeating/remembering them. But the problem is they don't increase in regular steps.. One day you learn more, other day less. I thought so it's more mathematical question, than physics.
  12. These details physicists learned most likely on studies.. So obviousness to scientists are skipped in PDF, to not bore reader. How about starting from learning everything from beginning.. ? It's not a problem making f.e. particle detector. Making your own Cloud Chamber costs $20. Device making couple millions volts you can have below $200. Device making x-rays you can have for $30 (Cockcroft-Walton generator). But you will need to build your own vacuum pump or buy one. It's a matter of how much serious you want to be in your science discovery. How much you want to spend money and time on it. ps. I can give you link to must-have devices for physicists in PM (where you could buy them).
  13. Do you know how to make x-rays.. ? Lacking in detail: because it's too much data. And you most likely don't know it. f.e. for every isotope (there is 3142 unstable/stable isotopes of 118 elements), there is needed different energy of photon to disintegrate. f.e. to disintegrate Deuterium there is needed 2.22 MeV energy. Scientists use highly accelerated alpha particle to hit Deuterium, so it'll split to free proton and free neutron. Neutron is then used for other experiments. f.e. Neutron scattering. Neutron capture. https://en.wikipedia.org/wiki/Neutron_scattering https://en.wikipedia.org/wiki/Neutron_capture
  14. How about photon-matter interactions, as showed in this video? Keywords for Google: photoelectric effect, Compton scattering, electron-positron annihilation, pair production, photodisintegration.
  15. Ionization of whatever you punched and thing that was used for punching, if more energy is used, then disintegration of atoms, they would separate to protons, neutrons, alpha particles, etc. f.e. to disintegrate Deuterium atom there is needed 2.22 MeV energy per nucleus. Actually it happens all the time in the atmosphere, at quantum level, highly accelerated incoming cosmic ray is hitting particle of air, or anything on the ground, and devastating it. Lucky, it's pretty low quantity. Otherwise there would be no living organisms (destruction of DNA chain, destruction of cells).
  16. My LEDs AFAIK have 20-25 mA at full bright. But let's it be 2 mA. It's still something like: 1.25*10^16 photons per second (idealized, assuming no lost).. How far do you want to go from it, if you have 1.25*10^16 photons emitted from LED per second? Do you know inverse-square law? (light from star, lightbulb etc.) If we apply inverse-square law to such quantity of photons per second, we have 1 photon per m2 of area per second, at distance equal to 31.5 millions meters from source..
  17. I fail to see how air ionization by laser, or doubling/tripling frequency are examples of overlapping photons.. After absorbing the first photon, excitation of electron in atom, takes some time. If yet another second photon excite it even further, before it go back to ground state, electron will reach higher energy level, and release even more energetic photon. Send beam of photons with E=10.2 eV (n=1 -> n=2) to Hydrogen, then another beam of photons with E=1.8889 eV (n=2 -> n=3), and you will get as a result photons with E=12.09 eV (n=3 -> n=1).. Laser used to ionization is generating exclusively polarized photons.. ? If two or more photons have different polarizations, then IMHO they don't overlap.
  18. I am not too much experienced with alternators, but in normal electric motors, the faster spinning, the higher voltage. So if it's exactly the same with alternators, which is what I suppose so. Spinning too fast (if there is nothing like regulator), could cause damage of electronics connected directly to it, in certain extreme situations. (Google shows plentiful of pages after searching for "alternator producing too much voltage", so it's real issue). In such situations, voltage threshold triggered branch with zener diodes could be used, f.e. Place fuse in horizontal branch instead of resistor. Zener diodes f.e. 15 V. If voltage is exceeding 15 V, current will flow through zener branch, instead of normal branch, and fuse will blow up, disconnecting entire circuit. Such (or other) security elements should be used in circuits, regardless whether current/voltage regulators are present. They might fail, and you need to be prepared for it in advance. Single zener diode costs here $0.05.
  19. See screen-shot, blue curve is initial input: blue = sin(time) So it's like AC. red curve is: red = abs( blue ) So it's like AC rectified to DC by 4 diodes/rectifying bridge. yellow curve is: yellow = max( blue, 0 ) So it's like AC rectified to DC by 1 diode. Source of AC, is pretty meaningless. Whether it's mains, or alternator, or electric motor spinning once in one direction, then other, theory works the same.
  20. Do you know OpenOffice? I attached project for calculator/excel. You can load and see difference between AC, DC pulses (output from rectifying bridge, or four diodes), DC rectified by 1 diode. Did you checked it in the real world experiment? Normally electric motors create DC while spinning one direction. Especially toy electric motors. You need 1 diode to do max(sin(t),0) (cut negative part of wave) and you need 4 diodes to do abs(sin(t)). That's how I draw graph in OpenOffice project. For normal single phase AC, 1 or 4 diodes are needed, no more, no less. No. If source of movement is changing direction of spinning motor, it'll be pulsating AC. If source of movement (whatever it is) just one direction, it'll be pulsing DC. And amount of pulse will depend on speed of spinning.AC DC DC pulses.zip
  21. I will give you +1 for seeking for knowledge.. All this is easy to see if you have oscilloscope and toy electric motor. Do you have? Connect electric motor directly to oscilloscope (because it shows past values on graph), or multimeter (it'll be harder). And start spinning it manually. You should see voltage is f.e. +some value on graph or display of multimeter. Then start spinning it opposite. You should see voltage is -some value. How large is this value depends on how fast you're spinning it by hand. source of energy is in this case spinning rotor of electric motor, so treat is as any other source of power. Attach it to rectifying bridge, and on output from bridge there will be pulsing DC. You would need four diodes, or one rectifying bridge. I am confused by your questions here. In showed by me design of electric motor, magnets are is stationary stator, and wires are around iron cores (electromagnet) in rotating rotor. It's not just one design of electric motor. It can be swapped (magnets in rotor, electromagnets in stator). It can have different quantity of magnets/electromagnets. It can be plain wire, without iron core. Why are you starting talking about charge regulators? When we're talking about electric motors. Not sure. Charge regulator https://en.wikipedia.org/wiki/Charge_controller "Simple charge controllers stop charging a battery when they exceed a set high voltage level, and re-enable charging when battery voltage drops back below that level." Such large quantity of pulses per second are almost only in electronic oscillators https://en.wikipedia.org/wiki/Electronic_oscillator Smoothing is needed to not constantly switch on/off whatever is using our generator. f.e. typical lightbulb is pulsing 100 per second, as it runs entirely on AC 50 Hz (50 Hz AC = 100 Hz pulses). This can be seen after recording at high rate camera (even 120 FPS recording is sufficient). Devices requiring steady DC current (electronics) wouldn't like it.
  22. Imagine body with temperature. It's emitting photons in the all directions, using inverse square law https://en.wikipedia.org/wiki/Inverse-square_law The higher temperature, the more energy have emitted photons. Bodies with low temperature are emitting photons in infrared, or microwave spectrum. Hot bodies such as stars are emitting photons in visible spectrum. These photons are absorbed by neighbourhood particles of gas, liquids, solids, and heating them. These gases, liquids and solids also emits their own photons to environment (otherwise their temperature and energy would be going to infinity, and they would be changing state, melting, vaporizing, ionizing. Radiation is a way to release too much energy in them). If emission meets absorption there is subtle equilibrium. Bodies heated in day (from Sun), will release accumulated energy at night time. If next day is not sunny, they'll receive little energy, and won't emit more than they have. We can use infra red cameras (expensive), or infra red thermometers (cheap), to learn body temperature from distance. They analyze spectrum of photons emitted by body to calculate temperature (typically invisible spectrum) to show on display (or make array of them width x height in camera case).
  23. 704 million years is half-life time. It's time needed to decay half of Uranium-235 isotope to it's daughter isotope. https://en.wikipedia.org/wiki/Decay_product Daugther isotope depends on decay mode. In case of Uranium-235, it's alpha decay, that's it, atomic number is decreased by 2, and mass number is decreased by 4 (or neutron number is decreased by 2). Z=92-2 = 90 protons. A=235-4 = 231 mass number. Isotope with Z=90,A=231 is Thorium-231. Giving overall reaction: U-235 -> Th-231 + alpha particle + 4.679 MeV energy released. Thorium-231 has plentiful of mass, approximately 231.0363043 u. So if you have 235 grams of U-235, after 704 million years you will have 235*0.5 = 117.5 grams of U-235, and 231*0.5 = 115.5 grams of Th-231. 117.5 + 115.5 = 233 grams. But because Th-231 is very unstable, it's also approximation, as it'll decay already within couple hours after making it.
  24. Rectifying diode is passing current one way, and blocking the other way (if it's not broken). Rectifying bridge (or four rectifying diodes) is turning sinusoid AC wave, to pulses in one direction current. Smoothing capacitor(s) will smooth these pulses to something more resembling flat DC. Electric motor is typically three or more electromagnets, and same quantity magnets. Not just one. Current passes through 1st electromagnet (wire+iron core f.e.), and creates magnetic field. This field is repelling from stationary magnet (polarization f.e. N on electromagnet and N on magnet). And rotor is spinning to 2nd position. Electromagnet is disconnecting from external power wires. After spin, 2nd electromagnet is connecting to these wires, powered up, and again repelling, and it's going in circle. Here you have example three electromagnet rotor: This one has 15-16 Also there is induction in ferromagnetic cores of electromagnets. If you connect DC to motor one way (+ to +, - to -), it'll be spinning in one direction f.e. clockwise, after swapping polarization of DC (+ to -, - to +), it'll be spinning in opposite direction. anti clockwise. After connecting AC to motor, it'll be spinning in one direction for some time (typically very short), and in other for some time. With high frequency AC, it'll be invisible spinning. Switching f.e. 50 Hz is so fast, rotor appears still. But you won't be able to spin it by hand. It will have great resistance for any manual spinning (unlike when power is turned off).
  25. It should be something like: <?php $string = $_GET[ 'data' ]; $result = Add( $string ); printf( "Result %d<br />\n", $result ); exit; function Add( $string ) { $result = 0; [... here you put all your code...] return( $result ); } ?> Replace contents of Add() by your code. Then test it, by going web browser to index.php?data=[string]
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