I Physics -- Need help understanding the concept of resonance please

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Resonance occurs at a system's natural frequencies, with each frequency corresponding to a different mode of vibration. The response of a system to these frequencies can vary, affecting different states or overlapping states. Key properties of these frequencies include gain and phase shift, which determine stability. At resonant frequencies, understanding the system's gain is crucial for predicting behavior, including whether it will stabilize or diverge. The concept of "time to double" is also important for managing any potential divergent behavior in the system.
danial3333
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I need help about the concept of resonance.
I will be thanksful if someone help me.

Please consider a system has two natural frequencies, and resonance will occur at two these natural frequencies. Now my question is what is different between these two renosances that has occured? And Which property do have those two natural frequencies?
 
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The response of a system to different frequencies can be handled separately and summed. It's not clear what you mean by "what is different" and "which property". A system can respond to different frequencies in the same axes, on different axes, or on overlapping sets of axes. The same can be said about the states of a system -- two resonant frequencies can affect the same states, different states, or overlapping sets of states. It can be analysed by looking at the eigenstructure of the (linearized) system.
 
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danial3333 said:
Please consider a system has two natural frequencies, and resonance will occur at two these natural frequencies. Now my question is what is different between these two renosances that has occured?

Each is the frequency of a different mode of vibration.

And Which property do have those two natural frequencies?

Frequency of vibration is a property of the system. It doesn't make sense to say that frequency has a property.
 
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A system will have certain properties at any frequency: gain and phase shift. The properties of a frequency are the frequency, wave length, and amplitude.
At a resonant frequency, it is important to know the system gain, which determines if it is stable or divergent. This includes frequency 0, which will either fade exponentially to 0 or grow exponentially to infinity. If the frequency is non-zero, the amplitude of the cycles will still grow or fade exponentially. One property that is nice to know is the "time to double", which tells you how much time there is to control any divergent behavior.
 
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Hello! Let's say I have a cavity resonant at 10 GHz with a Q factor of 1000. Given the Lorentzian shape of the cavity, I can also drive the cavity at, say 100 MHz. Of course the response will be very very weak, but non-zero given that the Loretzian shape never really reaches zero. I am trying to understand how are the magnetic and electric field distributions of the field at 100 MHz relative to the ones at 10 GHz? In particular, if inside the cavity I have some structure, such as 2 plates...
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