# Microwaves and Electro-magnetic waves (lame questions)

• I_am_learning
In summary: The 500 THz tank circuit is possible, but it would be incredibly inefficient. The signal inside the CPU is square or pulses with very fast rise time. Even the fastest 2GHz clock is sort of like a square wave and has odd harmonics. So I won't be surprised it has 6GHz and 10 GHz harmonics. Other slower frequency signals has high speed edge also and will have harmonics.
I_am_learning
Microwaves are said to be Electromagnetic waves with frequency 300 Mhz to 300 Ghz.
If so, then, is the CPU of my computer running at 2Ghz, emitting some sort of microwave ? Is the microwave cooking tiny drops of water around ?
(I say so, because, if the CPU is running at 2GHz, currents must be pulsing at 2Ghz, and that might create EM wave at 2Ghz).
Also, if I make some resonant electric Circuit to oscillate at 500 Thz, will I see some 'Red Lights' .
Also, if I static charge my plastic pen by rubbing against my hair, and then 'Wave' this charged pen at round 3 hz, will I be creating Radio Waves at 3hz ?

I_am_learning said:
Microwaves are said to be Electromagnetic waves with frequency 300 Mhz to 300 Ghz.
If so, then, is the CPU of my computer running at 2Ghz, emitting some sort of microwave ?
Yes, but at very low efficiency. The CPU microchip is a poor radiator because currents and their return paths (grounds) are very very close to each other. In other words, the sources are not connected to a good antenna.
I_am_learning said:
Is the microwave cooking tiny drops of water around ?
(I say so, because, if the CPU is running at 2GHz, currents must be pulsing at 2Ghz, and that might create EM wave at 2Ghz).
Well, yes if there is water nearby. The amount of power is absolutely tiny, however.
I_am_learning said:
Also, if I make some resonant electric Circuit to oscillate at 500 Thz, will I see some 'Red Lights' .
Yes
I_am_learning said:
Also, if I static charge my plastic pen by rubbing against my hair, and then 'Wave' this charged pen at round 3 hz, will I be creating Radio Waves at 3hz ?
Yes, but, again, this is a very weak source.

Thanks marcusl.
Well, its a pleasure to hear a 'Yes', to all of the questions. It saves me from 'editing' my knowledge. (Because, 'Yes' was what I was expecting). :)

Sorry, but your answers are incorrect - the 2 GHz refers to a clock speed at which the computer is running, not electromagnetic waves. If you have a watch that ticks of seconds, you can say the clock speed is 60 Hz (60 cycles/second) - that happens also to be the frequency of the AC voltage at your wall plug. That's a coincidence; they are not related, i.e. your watch and the AC voltage.

Part of the circuit in CPU actually runs at 2GHz, be it a small part, it can potentially emit EM wave at 2GHz be it very weak. Clock speed running meaning there is EM wave at 2GHz.

Remember AC electrical signal IS really EM wave propagation, not current or voltage traveling in the straight sense. Remember electrons move very slow, if it is current or voltage moving, things are very slow. The reason signal move in conductor at great speed BECAUSE it's the EM wave that propagates. Voltage and current measured are the consequence of the boundary condition of the EM wave in the transmission line...it this case, the traces inside the CPU.

Any imperfection in the guided structure, EM wave radiates out...most traces are microstrip and they leak!...Even inside the IC.

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surely any cpu clock running at 2 GHz is going to be an electrical oscillation at 2 GHz? so despite being very low power, and designed to pass EMC tests the principle is the same.

is a 500 THz tank circuit possible? that might be incredibly efficient lighting!

I forgot to mention, the signal inside the CPU are all square or pulses with very fast rise time. Even the fastest 2GHz clock is sort of like a square wave and has odd harmonics. So I won't be surprised it has 6GHz and 10 GHz harmonics. Other slower frequency signals has high speed edge also and will have harmonics.

Inside the CPU, even it's an IC, it has traces just like pcb, mostly microstrip that radiates. ON top, it behave just like pcb where emission happen when signal goes from one layer to the other and if the image current is not following, you have emission.

## 1. What are microwaves and electro-magnetic waves?

Microwaves and electro-magnetic waves are types of electromagnetic radiation, a form of energy that travels through space in the form of electric and magnetic fields. They are a part of the electromagnetic spectrum, which includes all types of electromagnetic radiation such as radio waves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays.

## 2. How are microwaves and electro-magnetic waves used in everyday life?

Microwaves are commonly used for cooking food, heating water, and warming up leftovers. Electro-magnetic waves are used in various technologies such as cell phones, television broadcasts, and WiFi signals. They are also used in medical imaging techniques like X-rays and MRI scans.

## 3. Are microwaves and electro-magnetic waves harmful to our health?

In small doses, microwaves and electro-magnetic waves are generally safe and do not pose a threat to our health. However, prolonged exposure to high levels of these waves can cause tissue damage and potential health risks. It is important to follow safety guidelines and limit exposure to high levels of electromagnetic radiation.

## 4. How do microwaves differ from other types of electro-magnetic waves?

Microwaves have a shorter wavelength and lower frequency than other types of electromagnetic radiation. This makes them less energetic and less able to penetrate solid objects, which is why they are used for cooking and communication rather than medical imaging or radiation therapy.

## 5. Can microwaves and electro-magnetic waves be used for communication?

Yes, microwaves and electro-magnetic waves are commonly used for communication in the form of radio waves, television broadcasts, and WiFi signals. They are able to travel long distances and penetrate buildings, making them an effective means of communication.

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