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

I think you know that power is directly proportional to energy. E=h*(new); 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.

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.

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.... thanx....

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.

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

For the electric frequency, please view the thread whose link is given below. http://www.crazyengineers.com/forum...-frequency-above-less-than-50hz-machines.html I have posted something in it which may interest you.

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.

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..

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

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

One persons say attenuation is independent of frequency in free space ,.... then says lower frequency higher distance, again challenged by someone please we get confused. It seems everybody is correct in their own explanation. But totally confused

I am working in GPS. we receive satellite signals at 1575.42MHz from thousand of miles distance . So my question is that whether there is no attenuation in signal between receiver and satellite.

Hey buddy 1575.42MHz=(approx) 1.5 GHz. In the GHz region there are certain bands of frequencies that are affected very less by Atmosphere and water particles in air. You can refer any microwave books for more details on this. And I am not clear of what you say here