Recent content by jainabhs

  1. J

    How Do Rotor and Stator Pole Numbers Affect BLDC Motor Efficiency?

    Thanks meBigGuy for pointing to this page. Although I have been to this page before, some how when I read it this time, I got slightly better idea what is going on. So it looks like if you have more rotor poles, you have to change the stator winding firing more rapidly than for less no of poles...
  2. J

    How Do Rotor and Stator Pole Numbers Affect BLDC Motor Efficiency?

    hi, There is one thing that I do not understand and nor do I find any direct explanations for it. Is there any relationship between no of rotor poles and no of stator poles in BLDC motor (or PM Synchronous Motor)? I have read somewhere there doesn't have to be. I can imagine if no of poles are...
  3. J

    Need tutorials on these topics

    I want to understand following, 1) Staistical Thermodynamics. 2) Equipartition theorem. 3) Ultra violet Catastrophe. 4) Black body radiation. 5) Wien's displacement law. 6) Boltzman's law. 7) Inception of Quantum mechanics. Can someone suggest any book? Or better would be some free...
  4. J

    How does frequency affect energy delivery in sine wave generators?

    Ok, I got that. Thanks. This is exactly what I wanted to confirm. Thanks again.
  5. J

    How does frequency affect energy delivery in sine wave generators?

    Thank you very much jtbell, Just one more thing to confirm. According to Planck's law, we need higher min energy to create one photon of high frequency than to create one for low frequencies, right? Thanks.
  6. J

    How does frequency affect energy delivery in sine wave generators?

    Consider following: The RMS value of any sine wave is Ampiltude/sqrt 2. It is independent of frequency. So consider two sine wave generators, one generates at 50 Hz and the other one generates at 500Hz. Both have same amplitude A for volt wave and B for current wave. Consider same pure...
  7. J

    EMwave in space and copper wire.

    Thanks, Now I know which book to refer :-)
  8. J

    How Does Temperature Affect Electromagnetic Waves?

    What exactly is tempertaure? As far as I know it represents the average vibration of atoms. How it relates to EM wave? because I have read in many Physics texts saying that 'the temperature of this wave is X Kelvin'. How do they find the temperature of individual EM wave? Correct me if I...
  9. J

    EMwave in space and copper wire.

    We have a formulae to find energy contained by an EM wave, which finds energy per unit volume. Also says it is equally distributed between E and B fields. How do we find EM energy for an EM wave of 50Hz in a copper wire? Because it is low frequency, instead of space we guide by conducting...
  10. J

    Understanding Spacetime Diagrams: Event E & Coordinates in K & K

    Hi I have some very basic doubts on spacetime diagrams. Please refer the figure attached. Here in this spacetime figure an event E is shown as observed from K and K'. K' moves with v with respect to K. The axis CT is tilted angle alpha following vt, so that any event that occurs at x' = 0...
  11. J

    Why objects with different mass fall with same velocity?

    So according to Pete if I take acceleration caused by free falling small mass into account, the velocity of free falling object would depend on mass m1 too. Hence every free falling object would fall with different velocity(I agree that the difference is very very negligible...)
  12. J

    Why objects with different mass fall with same velocity?

    Why objects with different mass fall with same velocity?? It is long said and proven that objects with different mass free-fall with same velocity. Suppose the mass of Earth is M and mass of an object in free fall is m1. As we know Earth's gravitational acceleration constant is g = 9.8m/sec2...
  13. J

    Understanding the Photoelectric Effect and Its Quantum Electronic Nature

    Below is my understanding of photoelectric effect, please correct me if I am wrong. It is an quantum electronic effect in which matter emits electrons after receiving energy in the form of EM waves. E.g. imparting X-rays on matter. So if we impart a high frequecncy wave (say f1) on a metal...
  14. J

    Calculate the force experienced by a fixed surface

    Hi, Can anyone tell me is there any way to calculate the force experienced by a fixed surface when hit by an object(of x mass) at say y height from the surface and accelerating towards it with 10m/s-sq? Is this force dependent on the surface(which i suppose yes but just for clarifaication)...
  15. J

    Understand 'One Form' Vector & Covariant - Relativity Demystified

    'one form' vector?? Hi I am reading a book 'Relativity Demystified' Please help with the following, I will appreciate any little help. What is 'one form' vector?? In the book the author says that --> A vector V can be represented with covariant Va. This type of vector is called one form...
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