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Sensei

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Everything posted by Sensei

  1. Search google for: snell's law diffraction single and double slit experiment you might also being interested about polarization filters. These things are cheap to buy in shop with physics equipment. Do experiments with lasers, and mirrors.
  2. Image not (hard to get image of particle at rest), but whole electrostatics is about measuring charges coming from electrons at rest that repel each other.. http://www.sparkmuseum.com/STATIC_MISC.HTM Wimshurst machine http://en.wikipedia.org/wiki/Wimshurst_machine Electroscope http://en.wikipedia.org/wiki/Electroscope Don't you have these devices.. ??
  3. See thread http://www.scienceforums.net/topic/84357-how-to-calculate-planck-const-at-home/ post #5 and #26 how you can calculate Planck const from just a few electronic elements and voltmeter, ampere meter etc.
  4. Maybe he will find peace now in his heart.. He appeared more and more pissed off. Perhaps we were giving him too much data..
  5. See section "Colors and materials" in article http://en.wikipedia.org/wiki/Light-emitting_diode There is table with data how drop of voltage on element is related to wavelength and color of photon emitted by LED. ps. Iwonderaboutthings had already trouble understanding all these informations, without going into such details.
  6. Actually, in coil electrons don't move in circle, but in spiral. Single electron is just once passing through wire. When electrons flow in one direction in coil of course it will produce magnetic field, that anybody with "compass array" device can see on his own eyes. But if we will use alternating current, electrons flow once in one direction, once in opposite direction. Can you detect magnetic field when frequency of AC would be counted in millions or billions Hz? What does show "compass array" device, if you will place it close to coil through which there is flowing low frequency AC, or high frequency AC.. ? What does show "compass array" device, if you will place it close to discharge tube with Hydrogen and turn high voltage on to ionize it.. ? The issue I see here is that spectral lines are obtained from discharge tube, with ionized plasma. But electric neutral Hydrogen gas is not mixture of proton and electron, but H2 molecule, two protons and two electrons. ps. Where in USA and UK somebody can buy "compass array" like below one? I searched couple times on Google and can't find anything.. Here it costs $40 in the regular shop. Whenever somebody asks on physics forum about "moving electron in circle around proton" I know they don't mean it literally. Circle is 2d figure, with missing one axis to 3d. Analyze should be done using the all 3 dimensions. What are your predictions of magnetic field lines around it for such "coil".. ? Imagine it's single long wire.
  7. Long traces in Cloud Chamber are from electrons (they are also called beta rays, or when we're making them using high voltage - cathode rays) The more kinetic energy has particle, the longer trace.
  8. It would violate conservation of energy, if electron would forever emit photons. It would means that electron has infinite amount of energy (which is obviously not true).
  9. That depends on what you do. I am using e as elementary charge everyday, to go from Joules to eV unit and reverse.. e as Euler number is used while calculating decay rate using mean-life, f.e.
  10. I was watching tv document about some South Indian tribe. One guy was complaining that now their children are going to school and teaching nothing useful. Complained about learning counting, learning letters and how to read ("where is bookstore in jungle?") He said that when he was young his father taught him how to fish, how to hunt, build house from wood and leafs.. Now his kids don't know how to survive in jungle..
  11. Do you feel heat on face when going outside in sunny day or while sunbathing.. ? That are billions of billions photons per second hitting your body, and increasing temperature of your atoms.. Increase of temperature is detected by nerve cells and informing brain about it. Put hand to strong laser > 1 W, and it will burn your body - large quantity of photons per small area unit per second will heat your body, and brain will be informed about damage, causing alarm, and reaction "run away". Continuous spectrum = infinite energy = black body/ultraviolet catastrophe.. http://en.wikipedia.org/wiki/Ultraviolet_catastrophe Average visible photon has wavelength ~532 nm so energy of such photon is h*c/wavelength = 6.62607e-34 * 299792458 / 532e-9 = 3.73e-019 J Sun is emitting at Zenith 1050 J/s of energy per m^2 (at least such amount is reaching ground at max). (I am simplifying calcs to not take care of UV/IR/MW - let's hypothetically assume the all is from visible spectrum) 1050 J / 3.73e-019 J = ~ 2.8e+21 photons per m^2 per second. That's average 2812 photons per 1 nm^2 per second of your face. More photons per area unit per second = more total energy = solid materials are melting, liquids are turning to gas, and in extreme situation gas is ionized (f.e. explosion of nuclear weapon, creates plasma inside). (and it can be used to cutting metals or other materials in laser cutting machines ) Some of these photons are absorbed, some are reflected (therefore other people can see you in day light), others are refracted. If your cloth is black, you feel hot, black surface is good visible photons absorber. while wearing white cloth, you feel better at summer, visible photons are reflected.
  12. It must be language barrier.. For me "work like radio receiver", is not the same as "work as radio receiver". "Because the underlying physics are the same... electromagnetic fields, for both sunlight" Sunlight is visible light. The "problem" with "working solar panel like radio receiver" (but for visible spectrum) is such that we WANT to get energy from photons with as wide as possible range. Limiting to just f.e. 650 nm +-10 nm would decrease output power from such device.. Radio receiver is receiving at wide range of wavelength - but it's electronics inside fine tunning to specific frequency (they overlap with all others).
  13. But solar panels generate electricity. Your setup is just heating water. For now you can use it to make a cup of tea or coffee in 6 minutes or so.
  14. Enthalpy, please reread his comment (post #20).. He didn't want solar panels to work with radiowaves frequencies..
  15. That depends on how to interpret passing through transparent medium with refractive index > 1.0.. If you will use beam splitter, one laser beam pass through air/vacuum, other one through container with f.e. water or other transparent fluid. Photons from the second one will arrive later..
  16. Lorentz transformation is designed for particles that have rest mass.. This message went through fiber wire on the bottom of ocean, with speed of light... You can take fiber wires with lengths 1 km, 10 km, 100 km, and emit light to them from the same source, and calculate delay on other end of fiber wire. You can send photons to satellite far away in cosmos, and measure delay of reply. And it'll be t=2*distance/c
  17. To heat 1 gram of water for 1 C, you need to use approximately 4.1855 J energy (XIX century calorie unit) So for 0.8 L it's ~800 grams (better measure mass, it'll be more precise than measuring volume) = 800 * 4.1855 J = 3348.4 J needed for 1 C increase. If it takes your device 13 seconds to receive such increase in temperature of water, divide it by time: 3348.4 J / 13 s = 257 W (= 257 J/s) No. As you can read on http://en.wikipedia.org/wiki/Sunlight it's max 1050 W/m^2 at Zenith. Your Fresnel lens have area 0.4731 m^2 0.4731 m^2 * 1050 W/m^2 = 496 W Receiving 257 W from max 496 W possible is not bad result IMHO for home made experiment. (and we don't know at what hour you did experiment). Fix video subtitles.. If I were you I would surround water container by mirrors from all sides (buy little aquarium and cut mirrors perfectly to match its borders), and leave just little hole on top for incoming light from Fresnel lens. You might also consider using vacuum flask, or surround it by Styrofoam.
  18. See in how many equations there is used h. You can reverse these equations. It's basic mathematics - searching for unknown y, when there is known x... y=f(x) Plug x to equation, and solve it, and you have y calculated. But in pure math, values are usually meaningless. While in physics, they're measured quantities from real world. E=h*c/wavelength so after reversing equation we're receiving: h=E*wavelength/c E = Q*U Q=I*t so E=I*t*U so you have h=I*t*U*wavelength/c I - current from ampere meter U - voltage from voltmeter t - time from stopper c - constant, but can be measured in experiment wavelength - can be measured using optics equations.. For single electron Q=e, so equation simplifies to: h=e*U*wavelength/c When U is less than 1.9 V, and wavelength is 650 nm, red LED won't emit light. If it's higher it's emitting light. Similar for green,blue,ultraviolet diodes, but different voltages U will be needed.
  19. Of course there is many ways to calculate h, or any other physical constant.. That's how we verify whether it's correctly calculated - checking it different method. In post #5 I gave you a way to measure it and calculate using electronic circuit, with just a couple instruments like voltage meter, ampere meter, stopper, with just a few equations.. h is derived from kinetic energy of electron needed to emit photon with well known energy/wavelength.. Instead of discussion how to make experiment we're again talking about some basic things unrelated to subject..
  20. Iwonderaboutthings, e is elementary charge when it is usually used in physics equation. e inside of value f.e. 1e6 = 1000000 is exponent in Scientific notation.. http://en.wikipedia.org/wiki/Scientific_notation e (equal to 2.71828....) is Euler number http://en.wikipedia.org/wiki/E_%28mathematical_constant%29 Used mostly in mathematics. Three completely unrelated usages of 'e'.... You HAVE TO know which one is used at the moment.. Every scientists know it from context of equation.
  21. Where did you see p for position? p is momentum in physics.. position is x
  22. I think you oversimplified this. In 1980 we had free access to hardware registers. And any program could do whatever machine allowed. Now that's job of operating system to talk to hardware. And regular programs have forbidden direct access to hardware.. You have to use OS functions to draw pixel on screen. You can't just set bit in bitplane.. This approach is required because different computers have completely different hardware, that program have no idea about.. Some people use linkable libraries for everything, usually beginners. Some people have to use linkable libraries, or dynamic libraries, because their internals are licensed, and if you would include it in your code, you could be accused of stealing.. So the same is nowadays..
  23. There is known a couple exotic atoms existing for a short time. http://en.wikipedia.org/wiki/Exotic_atom Positron coupling with electron: http://en.wikipedia.org/wiki/Positronium Muon- orbiting around nucleus/proton: http://en.wikipedia.org/wiki/Muonium Antiproton orbiting around Helium-4 nucleus: http://en.wikipedia.org/wiki/Antiprotonic_helium
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