What is Resonant: Definition and 203 Discussions

Resonance describes the phenomenon of increased amplitude that occurs when the frequency of a periodically applied force (or a Fourier component of it) is equal or close to a natural frequency of the system on which it acts. When an oscillating force is applied at a resonant frequency of a dynamic system, the system will oscillate at a higher amplitude than when the same force is applied at other, non-resonant frequencies.Frequencies at which the response amplitude is a relative maximum are also known as resonant frequencies or resonance frequencies of the system. Small periodic forces that are near a resonant frequency of the system have the ability to produce large amplitude oscillations in the system due to the storage of vibrational energy.
Resonance phenomena occur with all types of vibrations or waves: there is mechanical resonance, acoustic resonance, electromagnetic resonance, nuclear magnetic resonance (NMR), electron spin resonance (ESR) and resonance of quantum wave functions. Resonant systems can be used to generate vibrations of a specific frequency (e.g., musical instruments), or pick out specific frequencies from a complex vibration containing many frequencies (e.g., filters).
The term resonance (from Latin resonantia, 'echo', from resonare, 'resound') originated from the field of acoustics, particularly the sympathetic resonance observed in musical instruments, e.g., when one string starts to vibrate and produce sound after a different one is struck.

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  1. M

    Amplifier gain in resonant RLC circuit

    Amplifier gain ##A_V## is defined as the ratio of an amplifier's output voltage to its input voltage, i.e. ##\displaystyle\frac{V_R}{V}=\frac{IR}{IZ}=\frac{R}{R}=0.5## at 200 Hz. But this is absurd. Where have I gone wrong? Please nudge me in the right direction.
  2. C

    Speed of sound from resonant length of tube vs tuning fork wavelengths

    The graph is, I do not understand why how it is possible to find the speed of sound from the gradient for this graph. Can someone please help? Many thanks!
  3. B

    A How can I use a fiber EOM to lock a laser with a large input power?

    I am trying to buy an EOM for a PDH lock with a large laser input power and I was told I should go for a free space EOM. I see that they come as resonant and non-resonant, but I can't seem to understand the advantage of a non-resonant one. The resonant one seems to do pretty much everything the...
  4. LarryS

    Formula for Resonant Frequency of 2 Metal Coaxial Cylinders?

    Consider an LC circuit consisting of a parallel plate capacitor and a solenoid inductor in series. The formula for the resonant frequency of this circuit is 1/√(LC) where “L” is the inductance of the solenoid and “C” is the capacitance of the capacitor. Now consider a high-frequency cavity...
  5. M

    A Probability of resonant ionization

    Hello! I am trying to make some predictions for an experiment in which we have a first ##E_2## transition in an atom driven by a laser, and then we have a second laser that is ionizing the molecule only if the first laser was resonant (i.e. if the atom was excited). For the purpose of the...
  6. amgc63

    What is the length of each side of a resonant dipole to receive 12MHz?

    Hi, a question: Construct a resonant dipole to receive 12MHz. Answer; λ = c/f = (3x10^8) / (12 x10^6) = 25m The dipole length λ/2 = 12.5m The length of each side dipole is 12.5m/2 = 6.25m Im confused, isn’t it the answer is 12.5m? Why require to divide 12.5m/2 again to get the answer...
  7. M

    A Resonant frequencies of liquid in a cylinder

    Hi PF! I have been on and off working on a fluids problem for 2 years. I am SO close but the answer isn't coming out clean. I'll highlight the equations I solve and the technique. If you can help me finish this, I'll not only be incredibly grateful but I'll either thank you in the paper...
  8. B

    I Resonant Frequency Formula for a given object

    I know the v = λf is the formula to find the resonance frequency of a single continuous wave and the formula for resonance frequency of a spring is: 1/2π∗sqrt(𝑘/𝑚) but what about the Formula for a random object? a car, or a rock, water ? is there one Formula to rule them all? or do you...
  9. cianfa72

    Question about the energy stored in an RLC parallel resonant network

    Hi, I've a doubt about how to the energy is stored in a 'real' RLC parallel resonant network feeds from a sinusoidal source. Take a 'real' RLC parallel network having a resistor ##R_s## in series with the inductor ##L_s## (modeling its loss) with the capacitor C in parallel and consider it in...
  10. Elsi b

    Microwave generator and a resonant cylindrical cavity

    I tried to fix this physics problem. But i think I’m using the wrong steps.
  11. A

    Finding the resonant frequency of this "discriminator" demod circuit.

    This is the FM demodulation "discriminator" circuit. It is one of the simplest analog demod setups one could think of. An RF (FM) voltage signal is applied at V12 and the voltage at ' a' ' is supposed to contain the AF signal in its amplitude. The idea behind the circuit is that it resonates at...
  12. supak111

    Resonant frequency of a pipe submerged under water

    How do I calculate a resonate frequency of a length of pipe submerged totally under water? Do I just take speed of sound in water which is 1,481m/s at room temp, and decided it by length of pipe in meters multiplied by 4? so at 20 celsius water and 20cm pipe it would just be: 1481 / (.2 x...
  13. J

    Coupling of resonant modes in a 1D Photonic Crystal

    In 1D Photonic crystals, a defect can be introduced to create a defect/resonance mode and enable transmission. At first considerations, the thickness of the single defect layer determines the transmission frequency. Moreover, if it is a half-wavelength layer it will enable a resonance condition...
  14. G

    Plotting experimental results on resonant frequencies

    These are the questions that I can't figure out how to do. I have been assigned a lab report based on resonating frequencies on a string and am having trouble completing some of the questions in the report. This is what i currently have from the previous steps required. A bit of info...
  15. dRic2

    I Resonant cavity and circuit analysis

    As I understand, if you solve the Maxwell's field equations for a resonant cavity, supposing a time dependence of the form ##e^{iwt}##, you get an eigenvalue problem and different modes as possible solutions. I'm reading some notes where the author states that each mode can be associated with a...
  16. Guilherme Franco

    A Equipartition of energy in the modes of a resonant cavity

    I think the answer for this may be straightforward, but I don't see anywhere that explains this from the scratch: A large resonant cavity with a small hole is used to approximate an ideal black body. I understand the conditions for the modes inside the cavity. But there are two points that...
  17. D

    Calculating Spatial Current in Resonant Inductors

    Hello, I would like to replicate the results from the paper "wireless power transfer via strongly coupled magnetic resonances", but I'm having trouble interpreting their equations. I'm creating a MATLAB script to do so. In the paper, they get to a point where L and C are to be calculated in a...
  18. M

    A What Defines Waves as Resonant Generated?

    When we can say that the waves are : resonant generated waves ? the word resonance what presents?
  19. Edge5

    How Do Resonant MEMS Accelerometers Detect Changes in Acceleration?

    Hello, Suppose that I have a resonant MEMS accelerometer. It has a suspending beam (resonator) and I want to apply an AC voltage to the beam which will be at beam's resonant(natural) frequency. When I do this, I will create a standing wave pattern of acoustic waves (vibrations) inside the...
  20. K

    I Resonant frequencies of a membrane, dependance on Young's modulus?

    Hello, natural frequencies of (circular) membrane are expressed in every textbook as: where is the m-th positive root of the Bessel Function of the first kind of order n. For m=1, n=0: ξmn = 2,405. represents the radius of membrane, and is the velocity of wave propagation...
  21. B

    Resonant Lengths in open air column question

    Homework Statement An organ pipe 1.2m long and open at both ends produces a note with the fundamental frequency. If the speed of sound in air is 345 m/s, what is the fundamental frequency? Homework Equations Wave equation (f = v/lambda) The Attempt at a Solution My textbook solves the problem...
  22. M

    I Predicting the decay time of a resonant bandpass filter

    In a typical resonant bandpass filter, resonance is set as none at 0 and full at 1, such that the filter rings infinitely at 1 and not at all at 0. If there is a two-pole resonant bandpass filter, with an impulse excitation to a maximum amplitude of "1" and a resonance setting between 0 and 1...
  23. B

    Derivation of resonant frequency for SHM systems

    Homework Statement My question here isn't a specific question that has been given for homework, but a more general one. For an assignment I have to 'derive an expression for the resonant frequency, ω0' for two different systems, the first for 'a mass M connected to rigid walls via two springs'...
  24. Perodamh

    What is the resonant frequency and peak current drawn

    Homework Statement A series RLC current having a resistance of 40ohms and inductance of 400mH and a capacitance of 300microfarad is energized from 50Hz, 200V A.C supply. Find i) Resonance Frequency of the circuit ii) Peak current drawn by the circuit at 50Hz iii) Peak current drawn by the...
  25. D

    Calculating the resonant frequency of a gas cylinder

    I would like to make a bell out of a used compressed gas cylinder, but I would like to tune it to a specific note or frequency, e.g. A (440Hz). Can someone help with a formula to calculate this so I can cut it precisely?
  26. M

    Question on corner and resonant frequencies

    Homework Statement 1. An RC filter is constructed by modifying a voltage divider. The top resistor R1 = 3kOhms remains the same but the bottom resistor R2 is replaced by a capacitor C = 8nFarads. Determine the corner frequency fc for this filter in kHertz. 2. For an RLC circuit R = 12.4...
  27. N

    I Question about finding resonant box dimensions

    Hello! I hope I'm in the right place for this questions. In short, I'm a musical instrument builder. I'm looking at placing a piece of wood above a closed resonator box. The box (also made out of wood) will have a hole in the top that is centered under the piece of wood. I know the material that...
  28. Passionate Eng

    Resonant frequency of small particles

    Hi How can find the resonant frequency of small objects like dust particles? What factors affect the resonant frequency? And is resonant frequency dependent on size? i.e. if the resonant frequency of 1 cm3 of glass is some certain value, would it be the same for a larger size?
  29. C

    Relating resonant frequency to electrical impedance

    If a self oscillating electrical (passive) system is excited at two nodes A and B by a sinusoidal current, and if this system has one degree of freedom, then the response of the system is maximal at the resonance frequency. Quantitatively, this means that the ratio of the exciting complex...
  30. Sveral

    Resonant frequency of Volatile organic compounds

    Hello , could someone tell me ,where to find Resonant frequency of the chemical bond of the following Volatile organic compounds: Propene,Toluene,Benzene,Ethylbenzene. Thanks in advance .
  31. A

    Resonant Frequency and Transfer Functions

    Suppose I have some sort of a filter, whose transfer function is given by H(w), where w is the angular frequency of the input signal in radians per second. I want to know the maximum value of the transfer function. If I solve for the resonant frequency w0, which from my understanding is the...
  32. baldbrain

    Speed of Sound using a Resonant tube

    Homework Statement In the experiment for the determination of the speed of sound using a resonance tube, the diameter of the column tube is 4 cm. The frequency of the tuning fork is 512 Hz. The air temperature is 38° C in which the speed of sound is 336 m/s. The zero of the meter scale...
  33. Poetria

    Find Resonant Frequency of Spring-Mass-Dashpot System

    Homework Statement Consider the spring-mass-dashpot system driven by a sinusoidal force on the mass: (mD2+bD+k)x=F where sin(omega*t) Recall that for the unforced underdamped oscillator (b^2<4km, F=0), the value of the natural damped frequency omega_d=sqrt(k/m - b^2/(4m^2) Find the resonant...
  34. T

    I Resonant, non resonant neutrino oscillations and Dark Matter

    Hello I am aware that one method behind the production of right handed neutrinos is neutrino oscillation. Its been theorized that both non resonant and resonant neutrino oscillation can produce them I know that with non resonant neutrino oscillation the neutrinos don't reach thermal...
  35. T

    I Difference of resonant and non-resonant neutrino oscillation

    Hello Just wondering what the difference is between resonant and non-resonant neutrino oscillations. Are resonant neutrino oscillations called Mikheyev-Smirnov-Wolfenstein? Thank you
  36. C

    Engineering Parallel Resonant Circuit Frequency

    Homework Statement Homework EquationsThe Attempt at a Solution I'm not exactly sure why my formula isn't working here. The correct answer given to us is 2.25kHZ.
  37. B

    Why Didn't Glass Break When Tone at 775.195 Hz Played?

    I hit a glass and ran the sound though a FFT and I found the tone is 775.195 Hz. I then tried to play the tone out of my computer and this glass did not break. This is the equation I am using: Amplitude * Math.Sin(Math.PI * Frequency * n2 / 44100D) I set the Amplitude to 3 and the Frequency to...
  38. D

    What is the Resonant Frequency of a 2-Year Old's Outer Ear?

    Homework Statement A 2-year old child has an outer ear length of approximately 1.7 cm (compared to 2.5 cmfor an adult). Find the resonant frequency of the outer ear of the average 2 year old b.Draw a diagram of the natural harmonic for the child’s ear. Homework Equations f=v/waveleng where...
  39. raoxas

    Resonant circuit current calulation

    hello, collegues, I need to calculate current on the right circuit, but I don't really know how. I have the current in left circuit I and L1 L2 C1 C2. I have tried to calculate this using impedance and ohms law. As Z2=Xc+XL, and U2=jwM, where M - mutual inductance I think that I2 should be...
  40. R

    Resonant frequency of Piezoelectric material

    So i have a piezoelectric film deposited in the metal substrate and i want to determine the resonant frequency. Basically i can determine the resonant frequency base on the dimensions. But i need to proved it using experimental set-up. So i applied AC Voltage to the material then the material...
  41. K

    B How Many Layers of Aluminum Foil Are Needed for a Resonant Cavity?

    I want to build a Resonant Cavity to play with frequencies around 100-700 mhz. I'd like to try different shapes, so I was thinking in using a cheap malleable material like aluminum foil. Questions: - I think one layer of aluminum foil might be too thin.. If I paste a couple of layers will do...
  42. S

    Resonant frequency in acoustics

    Hi, A question popped into my mind which I've never thought of in 20 years of making music: when you hold a tuning fork against a simple resonator (a guitar body, a table, any object with some volume really), the resonator amplifies the tuning fork's sound and you hear the tuning pitch louder...
  43. Tom MS

    I Resonant Frequency of an Atom in an Atomic Clock

    Beam standard atomic clocks work by changing the magnetic state of a cesium atom by applying a microwave frequency that matches the resonant frequency of a cesium atom. What is this resonant frequency of the atom in terms of actual events that occur on the atomic level...
  44. jedishrfu

    The Tacoma Bridge Collapse was Not due to Resonant Frequency

    An interesting article on the Tacoma Narrows Bridge collapse of 1940 shown to students of physics throughout the years as an example of the power of resonant frequencies. However, the explanation was much too simple to be true. Here's the real story...
  45. A

    Why LC tank only oscillates at resonant frequency?

    I am wondering why LC tank only oscillates at resonant frequency not other frequencies? Is there a physics explanation for that?
  46. M

    Why does vibration always cause air to vibrate with it?

    When an object vibrates next to another object with the same resonant frequency it causes it to vibrate with it. Why is it that when an object vibrates, it always causes the surrounding air to vibrate with it?
  47. Z

    How to calculate the resonant florescent spectrum of 2-level

    I am working on calculating the interaction between 2-level atoms and an coherent laser field. I can calculate the radiation intensity versus time from the atoms. I want to calculate the spectrum now. I know the spectrum can be calculated as the Fourier transform of ⟨$\langle \sigma^\dagger...
  48. A

    Determine resonant frequency of an AC voltage source

    Homework Statement Given a series RLC circuit, with one R, one L, and one C element, and an AC voltage source with variable frequency, find the resonant frequency experimentally given an ammeter and a voltmeter. Homework Equations The current in the circuit when the circuit is in resonance is...
  49. J

    A question about resonant frequency

    hello, I'm a first year science undergrad, currently learning about mechanics and waves and so on there's this vine that's been going around, which shows someone playing a harp - here is the video in question; I personally find it quite beautiful and fascinating. Apparently the phenomena is...