What is Amplitude: Definition and 866 Discussions

The amplitude of a periodic variable is a measure of its change in a single period (such as time or spatial period). There are various definitions of amplitude (see below), which are all functions of the magnitude of the differences between the variable's extreme values. In older texts, the phase of a period function is sometimes called the amplitude.

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  1. T

    I Find input values for smallest function amplitude

    Hello! I have a function y(x) with variables a; b; c; d. I know what the values of a; b; c; d roughly should be, but I am trying to calculate them precisely, so the graph of the function over the region from a to a+90° would look as straight (horizontal with smallest possible amplitude) as...
  2. opus

    Finding amplitude, period, phase shift on uglier functions

    Homework Statement State the amplitude, period, phase shift, and vertical shift: ##y=\frac{5}{2}sec\left(\frac{π}{x}-4π\right)-2## Homework EquationsThe Attempt at a Solution [/B] Amplitude: Amplitude is equal to the absolute value of a. So the amplitude here is ##\frac{5}{2}## Vertical...
  3. J

    I Max Amplitude Gravitational Waves: 2?

    I am curious as to what the maximum amplitude of gravitational waves is. I have read that the maximum amplitude as such is equal to two but I cannot seem to find again a reference that states this clearly.
  4. C

    Remnant Magnetisation varying with input amplitude

    In a lab we had to measure the remnant magnetisation of a hysteresis loop with a permalloy core. The amplitude of the input sinusoidal wave was varied and the resulting remnant magnetisation measured. This was then plotted resulting in the remnant magnetisation varying sinusoidal with the input...
  5. K

    Amplitude of particles in progressive waves

    Homework Statement I don't understand how all the particles in a progressive wave can have the same amplitude. Surely they're all moving along the wave therefore cannot have the same amplitude. Homework EquationsThe Attempt at a Solution
  6. microsansfil

    I How the probability amplitude is estimated in practice

    Hi, I would like to know how the amplitude of probability is estimated/determinated in practice, for a given experiment. In this example 1.3.2 Analysis of Experiment 2 it is assumed that the probability for each of the two possible states are equiprobable. Than from the experimental results...
  7. J

    Amplitude of waves at a further distance

    Homework Statement While sitting in a large pool that has a wave generator situated in the center, you text your friend, who is sitting much closer to the wave generator. If the amplitude of the generated wave is A at your friend's location from the generator (d=5.0m), what is the amplitude of...
  8. redtree

    I Normalization and the probability amplitude

    Given two probability amplitude wavefunctions, one in position space ##\psi(r,k)## and one in wavenumber space ##\phi(r,k)##, where ##r## and ##k## are Fourier conjugates, how is it possible for the modulus squared, i.e., probability density, of BOTH wavefunctions to be normalized? It seems...
  9. C

    Find the maximum amplitude of the induced EMF

    Homework Statement [/B] A radio transmitter radiates isotropically at the frequency of 90.8 MHz. The peak magnetic field at a receiver, 9km from the transmitter, is ##9x10^{-10}T##. Calculate the maximum amplitude of the induced emf in a 12 turn coil with area A = ##90cm^{2}## at the receiver...
  10. E

    How can we double the amplitude of an oscillator?

    Homework Statement The amplitude of any oscillator can be doubled by: A. doubling only the initial displacement B. doubling only the initial speed C. doubling the initial displacement and halving the initial speed D. doubling the initial speed and halving the initial displacement E. doubling...
  11. slow

    B Amplitude of a photon's E and B fields

    Hi. Please let me know if the question is misplaced in the quantum forum. Is the next. Exist, in quantum terms, the electric and magnetic fields corresponding to a single photon? If yes, add another question. Is there any way to formulate the amplitudes of both fields in electrodynamic terms...
  12. S

    Negative square amplitude for a decay process

    Homework Statement I'm trying to compute the square amplitude ## |\mathcal{M}|^2 ## for a decay process in which a Majorana fermion, call it ## \chi_2 ##, decays into another Majorana fermion, ## \chi_1 ##, and a vector boson denoted by ## A^{\mu} ##. The model is such that the mass of the two...
  13. A

    What amplitude of simple harmonic motion of the spring....

    Homework Statement Answer: Can someone explain the answer? I don't understand why it's necessary for that the moment when the force exerted on the smaller block is greatest is when it is on the verge of slipping. Could it not already have been slipped off or maybe even 3/4 way slipped off...
  14. R

    Composition of Light: Questions & Answers

    Hi everyone, I have a few questions about the composition of light: First, what is it? Is white light the result of all color wavelengths present in an area? Second, if so, then why is there no interference in waves of light (or is there)? Third, if photons all travel at the same speed, then...
  15. K

    Pitch and amplitude of sound wave Vs its volume

    Hi. If I know the pitch and amplitude of a sound wave, will I be able to calculate its volume. I can understand volume of devices vary betwerb brands and other categories. For the sake of discussion, let's assume volume to be a consistent unit or if db is the right unit, let's take that.
  16. A

    Exponential decay of a pendulum oscillation amplitude

    Homework Statement I found an answer on the internet for this problem, but I'm not sure on one of the steps. The solution says, "Take ln of both sides to get rid of Ae. If we do that, then the right side will be ln(Ae^t/T). I don't see how using ln will get rid of Ae? Homework Equations Refer...
  17. Hydrous Caperilla

    Finding Amplitude of the Oscillation

    Homework Statement A A man applies a Force F on a spring block system shown.towards right when the block is at rest and spring is relaxed .If F is constant then [/B]Homework Equations : F=-kx[/B]The Attempt at a Solution The equilibrium position will be at the position where the disturbing...
  18. V

    Amplitude of SHM of a spring hung from a ceiling

    Homework Statement A point mass of m = 20 kg is suspended by a massless of constant 2000N/m. The point mass is released when the elongation is 15cm.Find equation of shm Homework Equations F= - kx The Attempt at a Solution [/B] I'm not sure what this question is trying to say honestly...
  19. morrobay

    Amplitude of Wave at 5pi/6 Radians in Cycle, y = Asin(kx-wt)

    Homework Statement λ = 3m T = .5 s k= 2π/λ = 2.09 radians/m ω= 2π/T = 12.56 = radians/sec v = ω/k = 6m/sec At π radians with sin wave x = 3m At 5π radians/6, x = 2.48 m t = 2.48m/6m/sec = .41 sec What is y at x,t At t0 x = t = 0 [/B]Homework Equations y = Asin(kx-ωt)[/B]The Attempt at a...
  20. AbigailG

    Finding Amplitude of spring oscillation after damping

    Homework Statement [/B] A spring with spring constant 10.5 N/m hangs from the ceiling. A 520 g ball is attached to the spring and allowed to come to rest. It is then pulled down 6.20 cm and released. What is the time constant if the ball's amplitude has decreased to 2.70 cm after 60.0...
  21. bahtiyar

    Swing and angular displacement

    hi, we are a few non-native English speaker physics teacher and we wrote some questions for an assessment book but we can't be sure about this two similar question. a) are they accurate for rules of English, are we use correct terms is there a necessary change? b) are they accurate for rules of...
  22. V

    Interpret constraints on scattering amplitude

    Homework Statement For the following theory: ##\mathcal{L}=\frac{1}{2}[(\partial \phi)^2-m^2\phi^2+(\partial\Phi)^2-M^2\Phi^2]+g\phi^2 \Phi^2## Compute s-channel amplitude for process ##\phi\phi \rightarrow \phi\phi##. Interpret result for ##M>2m##. Homework Equations Scattering amplitude...
  23. F

    I Amplitude decaying sine function

    Hello, I am numerically plotting a sine function sin(x) with amplitude 1 from x=0 to x=15. No problem with that. The next step gives me problems: I would like the sine function amplitude to decay exponentially starting at x=5 and not before that (the amplitude remains 1). I think I need to...
  24. D

    I How does one make an Amplitude vs. Frequency plot?

    I am working on homework for a physics lab course and I am asked to write a python function which will produce an amplitude v.s frequency plot. In a previous problem I wrote a function which simulates data from a sine wave in the form of a time series; the new function should be able to take...
  25. O

    I Amplitude to go from one state to another

    I have a question about probability amplitudes to go from one state to another. I think it'll be clearest if I start with the case that I understand. Suppose I start in some initial state |ψ>, and I let it evolve over time t to some state eiHt/ħ|ψ>. Now, if I want to know the probability that...
  26. T

    Refraction Convergence and Amplitude change- Ocean waves

    There are many explanations on the internet, of refraction and convergence of ocean waves entering shallow water around a headland However they all go no deeper than this statement "Where the water is shallow the wave rays converge wave energy is greater where the wave rays spread out the...
  27. W

    RLC Circuits - Q Factor and Amplitude

    Homework Statement Imagine you have two RLC circuits you are trying to scan for resonances. They have identical resonant frequencies, but circuit 1 has a very high Q-factor (Q1 >> 1), and circuit 2 has a very low Q-factor (Q2 < 1). Let's assume you are already on resonance and looking at V(out)...
  28. P

    Mass-spring question (frequency and amplitude)

    I am confused by this question and was hoping someone could clear this up for me, I know this is simple. A mass-spring system vibrates at 10 Hz. Ideally, i.e., without friction, it would continue forever at the same amplitude. In practice, its amplitude is found to decay such that it decreases...
  29. F

    Finding the Amplitude of a Trigonometric Motion Equation

    Homework Statement Find the amplitude of the motion given by x(t) = C cos ωt + D sin ωt. Homework Equations [/B] x(t) = C cos ωt + D sin ωt The Attempt at a Solution [/B] x(t) = C cos ωt + D sin ωt x’(t) = -Cω sin ωt + Dω cos ωt 0 = -Cω sin ωt + Dω cos ωt 0 = -C sin ωt + D cos ωt C sin...
  30. K

    B Why the energy that waves transfer is only dependent on amplitude

    Hi, I wonder why the energy that waves transfer is only dependent on amplitude? E.g. in this animation: http://lifecdn.dailyburn.com/life/wp-content/uploads/2015/02/2.Alternating-Slam4.gif The waves on the rope transfer energy to the items on the right side. Wouldn't there be transferred...
  31. N

    Equation for the amplitude of a line sweeping across a triangle

    Homework Statement I have a triangle with top sides of 5 mm (base is then 5*sqrt(2)). The top triangle has a line cut through it, at a height of 5/sqrt(2)/2. I want to compute the amplitude as function of position as a line sweeps into the triangle that is cut off. Requirement is A(0) = 0 and...
  32. peroAlex

    Electromagnet with two cardboard pieces

    Hello! Recently I was going through some old exams and upon encountering this problem (which seemed pretty easy) I got stuck. Exams at my university are composed of individual tasks, each having three subquestions with four plausible answers respectively. Solution sheet gives results only, so...
  33. S

    I Dirac vs KG propagation amplitude

    Hello! Can someone explain to me the physical meaning of ##\bar{\psi}=\psi^\dagger\gamma^0## in the Dirac equation? For example when calculating propagation amplitude I see that what we calculate is ##<0|\psi(x)\bar{\psi(y)}|0>## and not ##<0|\psi(x)\psi(y)|0>## (as we do for KG equation) and I...
  34. T

    Maximum Amplitude of Sound Wave?

    This animation demonstrates a longitudinal wave by means of moving bars. I realized that if we increase the amplitude of the wave, the bars will eventually start passing through each other, which sounds (no pun intended) like an unphysical scenario. Does this mean that there is a cap, a...
  35. S

    Amplitude and wavelength of longitudinal wave

    Homework Statement A wave is shown below. The dots represent the particles of the wave at a time t = 0 s, and the vertical lines represent the positions of the particles before the wave arrives. Find the amplitude and wavelength of the wave Homework Equations Not sure The Attempt at a...
  36. Tulio Cesar

    Relation between sound intensity and frequency

    The sound intensity formula is given by: dE/dT*dS. So the variables are energy, related to the amplitude of the wave, area, related to wavefronts distribution on space, and time. So many times I don't see any reference about the relation between frequency and sound intensity, but if time is a...
  37. L

    Computing the scattering amplitude from the S-matrix

    Homework Statement Consider two real scalar fields \phi,\psi with masses m and \mu respectively interacting via the Hamiltonian \mathcal{H}_{\mathrm{int}}(x)=\dfrac{\lambda}{4}\phi^2(x)\psi^2(x). Using the definition of the S-matrix and Wick's contraction find the O(\lambda) contribution to...
  38. redtree

    A Deriving Probability Amplitude from Markov Density Function

    1. Given a Markov state density function: ## P((\textbf{r}_{n}| \textbf{r}_{n-1})) ## ##P## describes the probability of transitioning from a state at ## \textbf{r}_{n-1}## to a state at ##\textbf{r}_{n} ##. If ## \textbf{r}_{n-1} = \textbf{r}_{n}##, then ##P## describes the probability of...
  39. Daniel Petka

    B Probability Amplitude: Understanding Photons

    https://www.physicsforums.com/attachments/197770The path of a photon is a perfect straight line not a sine wave, right? (if the probability amplitude is zero)https://www.physicsforums.com/attachments/197771
  40. S

    What Is the Correct Source Voltage Amplitude for Desired Power in an AC Circuit?

    Homework Statement An ac series circuit consists of a voltage source of frequency f = 60 Hz and voltage amplitude V, a resistor of resistance R = 163 ohms and a capacitor of capacitance C = 6.2x10^-6 F. What must the source voltage amplitude V be for the average electrical power consumed in...
  41. whatphysics

    Amplitude spectrum vs frequency spectrum

    What is the difference between amplitude spectrum and frequency spectrum? In signals and systems.
  42. TheBigDig

    Acceleration amplitude of a damped harmonic oscillator

    Homework Statement The acceleration amplitude of a damped harmonic oscillator is given by $$A_{acc}(\omega) = \frac{QF_o}{m} \frac{\omega}{\omega _o} \sqrt{\it{R}(\omega)}$$ Show that as ##\lim_{\omega\to\infty}, A_{acc}(\omega) = \frac{F_o}{m}## Homework Equations $$\it{R}(\omega) =...
  43. F

    Trouble finding the amplitude in a SHM problem

    Homework Statement a horizontal spring-mass is composed of a spring with constant 10.0 N/m and an 80.0 gram mass on the end of the spring. the surface supporting the mass is friction less. when the system is first observed, the spring is extended 1.30 cm and the velocity of the mass is 54.1...
  44. A

    How do I find the amplitude of the combined signal?

    Homework Statement Homework Equations Δφ = 2π (Δr/λ) The Attempt at a Solution I understand how to get the phase difference, but is the equation for the combined wave (second last line) just something I should memorize? Also, where does the sin term go in the last line? And why are the...
  45. asteeves_

    Calculating Amplitude in Simple Harmonic Motion

    I have encountered two separate review problems that have to do with finding a value for amplitude and I am really struggling with it. 1. Homework Statement Question 1- A mass of 3kg is free to move on a horizontal frictionless surface and attached to a spring of k=15 N/m. It is displaced...
  46. S

    I Amplitude moving through detectors

    We have two thin parallel detectors, and a ##|1\rangle## photon state passes through them. Each detector has a 10% chance of catching the photon. How can I write the final state? I'm thinking something like ##\sqrt{0.1}|1_A\rangle |0_B\rangle |0\rangle+\sqrt{0.09}e^{-j\theta_1}|0_A\rangle...
  47. Frov_ken

    Finding the power from the electric field amplitude

    Homework Statement I am modelling a ray-tracing algorithm(image method), and I am in the part where I am getting the summation of all EM "rays" hitting the receiver. I come to a problem where I can't properly convert and unsure to do so. Ideally, I should have a collection of Ei waves defined...
  48. John Doe

    I Amplitude of particles in the medium of a longitudinal wave

    I was thaught you can create a sinusoidal wave by making a source oscillate with simple harmonic motion in a medium, such as moving one end of a rope up and down to create a periodic transverse wave. For transverse waves, it is easy to see that every particle in the rope moves up and down with...
  49. T

    SHM Amplitude vs. Frequency graph

    Homework Statement A metal hangs vertically from one end of a spring. The other end of the spring is tied to a thread that passes over a pulley and is attached to a vibrator, as shown in the figure. The vibrator is now switched on. The frequency of vibration is varied from 0.7f to 1.3f where...
  50. M

    Calculating Magnetic Field from FFT Amplitude

    So a little bit of background: I work in an undergraduate lab at UMass Amherst and am currently building/optimizing a faraday magnetometer for use in the Muon g-2 experiment at Fermilab. The magnetometer works as follows. A laser is shone through a crystal with a particular Verdet Constant at...
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