Intensity and frequency of radio waves

In summary, the conversation discusses the relationship between energy, frequency, and intensity in electromagnetic waves. The energy of a single photon is proportional to its frequency, and the intensity is the amount of power transferred per unit area. Increasing the frequency or voltage can increase the intensity, but the number of photons emitted per second must also be taken into account.
  • #1
mariano54
21
0
Hi, I am not a physicists and have been trying to understand some basic concepts about electromagnetic waves in the context of telecommunications.

Now, this is what I know so far: the energy of electromagnetic waves is proportional to it's frequency (E = h*f), and basically it's the energy carried by a single photon.

The intensity of an electromagnetic wave is the amount of power transferred per unit area, and can be described as the amount of photons * energy per photon.

IF these assumptions are correct, then the intensity could be increase in two ways: by increasing the frequency (energy per photon) or by increasing the voltage used to generate the wave (number of photons). Either of these two would yield more energy transferred and therefore higher intensity.

Is this reasoning correct?
 
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  • #2
mariano54 said:
Now, this is what I know so far: the energy of electromagnetic waves is proportional to it's frequency (E = h*f), and basically it's the energy carried by a single photon.

I would say rather, that the energy of a single quantum (photon) of an electromagnetic wave is proportional to its frequency via E = hf.

Usually, an electromagnetic wave "contains" many many many [...] many many photons, so its (total) energy is some very very very [...] very very large multiple of hf.
 
  • #3
So is it logical to think that by increasing the frequency, the intensity at a distance A meters would be greater than with lower frequency?
 
  • #4
mariano54 said:
So is it logical to think that by increasing the frequency, the intensity at a distance A meters would be greater than with lower frequency?

Yes - if you made sure that your transmitter was radiating the same number of Photons per second. That is an unlikely scenario because transmitters tend to operate on the basis of Volts and Amps - i.e. Watts - in which case, for a given radiated power, the number of Photons would be inversely proportional to the frequency of the transmission.
 
  • #5
It is not difficult to calculate the number of photons emitted per second required to emit a particular power.
If a light bulb emits 100W (100J/s) of yellow light then by using E = hf (with f = FREQUENCY of yellow light) you can calculate the number of yellow photons emitted per second.
If it is 100W of gamma radiation you will get a vastly different answer.. You can usually detect individual photons of gamma radiation (clicks on a geiger counter) but you cannot easily detect individual yellow photons.
 

What is the relationship between intensity and frequency of radio waves?

The intensity and frequency of radio waves are inversely related - as the frequency increases, the intensity decreases and vice versa. This is known as the inverse square law, where the intensity of a wave decreases with the square of the distance travelled.

How is the intensity of a radio wave measured?

The intensity of a radio wave is measured in watts per square meter (W/m²). This measures the amount of energy that passes through a specific area in a given amount of time. It is important to note that the intensity of a radio wave decreases as it travels farther away from its source.

What factors affect the intensity and frequency of radio waves?

The intensity and frequency of radio waves can be affected by various factors such as the power of the transmitter, the distance from the transmitter, and the presence of obstacles or interference in the path of the waves. Additionally, the frequency of radio waves can also be affected by the material they are passing through, with different materials having different levels of absorption and reflection.

Can exposure to high intensity and frequency radio waves be harmful?

Exposure to high intensity and frequency radio waves can be harmful in certain situations. For example, if a person is exposed to high intensity radio waves for a prolonged period of time, it can cause heating and damage to their body tissues. However, the levels of radio wave exposure from everyday devices such as cell phones and Wi-Fi routers are well within safe limits and have not been found to cause any harm.

How are radio waves used in communication and technology?

Radio waves are used in various forms of communication and technology, such as radio broadcasting, television broadcasting, cell phone networks, and Wi-Fi. They are also used in radar systems for navigation and in medical imaging technology such as MRI machines. The ability of radio waves to travel long distances without the need for physical wires makes them an essential tool in modern communication and technology.

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