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Relation between frequency and power

Discussion in 'Electrical | Electronics | Communications' started by qaisarpk1, Aug 13, 2010.

  1. qaisarpk1

    qaisarpk1 Apprentice

    what is relation between frequency and power ...
    which frequency travel long distance... low frequency or high frequency?
  2. mohit007kumar00

    mohit007kumar00 Apprentice

    I think you know that power is directly proportional to energy.
    where new represent frequency of the signals.
    so you can say that power is directly proportional to frequency.
    frequency is inversely proportional to time so and time is directly proportional to distance.
    So with low frequency you can travel more distance.
    low frequency->more time->>more distance.
  3. Voltaire

    Voltaire Certified CEan

    In terms of electricity there is no relationship. Electrical power is simply the product of the current and the voltage.
    The lower the current is the less resistance there is to the current flowing through the conductor. That is why electrical power is transformed to high voltage (low current) when it is transmitted over long distances. This is a property of an electromagnetic wave i.e. wave particle duality.

    The frequency of light does however affect the energy of the light wave viz. E = hf where h is Planck's constant and f is the frequency. Since c = fl, f = c/l. This simply implies that the frequency is a way to describe the rate of wave formation i.e. so may times per second and so we can say that the energy of a light packet is equal to some number multiplied by how many times per second the wave regenerates.
  4. qaisarpk1

    qaisarpk1 Apprentice

    its fine mohit .....
    as u said that the lower frequncy travel more distance then why we modulate low freq signal on higher frequencies ....
    kindly explain one more thing that why we use higher freq in satellite comm instead of lower freq as lower freq travel more distance....
  5. Voltaire

    Voltaire Certified CEan

    Could someone please formulate a mathematical relationship and provide an answer to the following question:

    A nano-car travels on the edge of a light wave i.e. in a sinusoidal pattern. Remember that the speed of light is constant and hence our little car has to travel at some theoretical speed greater than c[/c]. The little car first travels on a wave with wave lenth l and then on a second light wave with a frequency double that of the first wave.

    Q: on which wave does the little car travel the furthest distance in one time period.
  6. reachrkata

    reachrkata Apprentice

    Ah !!! Unfortunately, lower the frequency greater is the antenna size required to radiate that frequency. It follows the lambda/4 relationship.

    - Karthik
  7. aj_onduty

    aj_onduty Certified CEan

  8. Ah, how did I miss this??

    Actually, lower the frequency, LESSER is the distance it can travel before it gets attenuated too much, or get corrupted by noise.

    Higher the frequency, lesser is the attenuation. Which means, higher the frequency, greater is the distance which the wave can reach with reasonable attenuation levels.

    This is the reason we modulate baseband signals to high frequencies in radio communication, It's also the reason for very high frequencies in case of satellite communications.
  9. lord_slayer

    lord_slayer Certified CEan

    silverscorpion you got the concepts reversed there.. Lower the frequency LARGER is the distance it can travel.. and vice versa.. The reason for high frequency communication in satellites is that we can't have large antennas hanging around in space..
  10. vikash_pandey

    vikash_pandey Newbie

    well mr. silver i have a question,
    if signal attenuation is more in low frequency signal then why there is more attenuation in 30/20 GHz band in satellite communication as compared to 6/4 GHz band.
    Thank You
  11. Satellite are not very close to earth and air media travelled by these waves have ions(ionosphere) and so there is no ideally unity permittivity

    That tells us the actual reason

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