Rms Definition and 203 Threads

Why do we use the square of the graph as opposed to the absolute value of the graph to find the mean values?

I have a CW laser system, the optical detector receives a pulse width modulated signal and converts it to an analog signal. Both the source and detector have 32 channels and I would like to know what the analog signal power is, I thought maybe I could use the RMS voltage received on the...

Hi, For a single phase full wave fully controlled bridge rectifier carrying a RL load, how is the RMS voltage and current calculated? I have researched textbooks but can only seem to find RMS equations for Resistive loads and I am not sure whether the negative load voltage will affect the...

Homework Statement The question is as stated: "The ##H_2## molecule has oscillatory excitations. In classical physics the energy can be approximated to \begin{equation} E = \frac{p^2}{2m} + \frac{m \omega^2 x^2}{2} \end{equation}where m is the reduced mass. Quantum mechanics can be applied to...

Could someone explain to me the intuition behind RMS values? I understand how you calculate them; you take the average of the squares and square root them. I am just wondering why. For example when it comes to voltage, how did someone just think up of this magical way to compute an effective...

Homework Statement I had two small questions about the following problems. 1. Find the average and RMS values of the following waveform: 2. Show that the average and RMS values of the following sawtooth are independent of the position of the peak and are given by ##0.5## and ##0.577## of...

I am confused about very fundamental question. Why does the rms value of number of electrons collected from a signal(like in photoconductor) gives you the noise in that signal.

I just bought a few car audio amplifiers, they are advertised as 6000 watts and 800 watts respectively but the fuse ratings are 60ampsx2 and 20ampsx2 so am I missing something here? I purposely bought higher wattage amps because I believe their only advertising peak power (assuming they use...

This is just a quick question: A problem I'm working on says "a sinusoidal current of .5 amps (rms) and 5 kHz." Later, in the problem solution, I(t) is written as .5 \sqrt{2} \cos{(10^4 \pi t)}. I think I'm simply misunderstanding something about the construction of a current function when...

consider a sin wave to find the average of this function over interval 2pi, why not just do... $$\frac{1}{2\pi}\int |sinx|dx$$ this turns out to be.. $$\frac{4}{2\pi}= 0.63619$$ the whole purpose of squaring and then sqrt'ing at the end is to make sure there are no negative...

Every 50μs I have access to one sample of an unknown peroidic input signal and I am looking to calculate the RMS of the fundamental component. Is there any convenient ways one can think of doing this?

Sorry if this sounds like a dumb question, but why is the effective value of a sine wave 0.707, as opposed to 0.637 which is the value generated by finding the definite integral over the domain [0,∏] divided length of the domain?

I was wondering if there is a mathematical difference between the RMS free path and the mean free path of molecules in an ideal gas. For example, When I calculate the mean free path, I use use the average velocity and the scattering rate which is a function of the average velocity. I then...

The rms speed for a particle in a gas can be calculated using the formulae: u_{rms}=\sqrt{\int(u^{2}n(u)du)/N} a) Use the formulae and the expression for n(u): n(u)=(\frac{2^{1/2}N}{\pi^{1/2}})(\frac{m}{k_{B}T})^{3/2}u^{2}exp(-\frac{mu^{2}}{2k_{B}T}) To estimate the rms speed of Ne...

Homework Statement An ideal gas is kept in a container of constant volume. The pressure of the gas is also kept constant. The number of molecules in the gas is doubled. If the initial rms speed is 1300m/s, what is the final rms speed? Homework Equations Vrms=sqrt[(3kT)/m] PV=NkT...

Hello everyone, When I was studying about the way to find the RMS speed of an ideal gas by using classical mechanics, I wondered that why the time interval of the collisions can be approached as the time between two collisions, instead of contact-time between particle and wall. remember...

Homework Statement Find vrms from the Maxwell speed distribution. Basically what I need to solve is the integral a\int_0^∞ \! v^4e^{xv^2} \, \mathrm{d}v Where ##a## and ##x## are constants. Homework Equations $$a\int_0^∞ \! v^4e^{xv^2} \, \mathrm{d}v $$ Where ##a## and ##x## are...

Homework Statement The series combination of a 1 kΩ resistor and a 2 H inductor must not dissipate more than 250 mW of power at any instant. Assuming a sinusoidal current with ω=500 rad/s, what is the largest rms current that can be tolerated? Homework Equations Uploaded The...

Homework Statement A container having a volume of 1m^3 holds 5 moles of helium gas at 50C. If the helium behaves like an ideal gas, the rms translational kinetic energy is? Homework Equations Total E= 3/2 nRTThe Attempt at a Solution I tried solving this question using this equation, but I did...

Homework Statement The problem is located here http://www.chegg.com/homework-help/determine-average-rms-value-waveform-depicted-fig-1136-chapter-11-problem-26e-solution-9780073529578-exc Homework Equations Rms=sqrt(1/T∫ from 0 to T of i(t)^2 DT ) Average= couldn't find an equation in...

Hi everyone, I'm new here and this is my first post in this forum. ^^ Homework Statement Suppose that you observe a fluorescent object whose true location is x0. Individual photons come from this object with apparent locations xi in an approximately Gaussian distribution about x0...

Hey everyone, just got a quick question in acoustics. I am mainly looking for a mathematical understanding Homework Statement Consider two harmonic plane progressive waves of the form \tilde{P(x)} = \tilde{A}e-jkx and\tilde{P(x)} = \tilde{B}e+jkx traveling in opposite directions. Showing...

Trying to find rms current at resonance and rms voltage across each elements (resistor, inductor and capacitor) I got the answers but i want it do in multisim ! i got : R = 500 ohm L = 0.40mH C = 100pF The answer is rms current: 0.002A rms voltage: Vr = 1V Vc = 126.52 V Vl = 126.52 V...

Homework Statement Calculate the average power (P) absorbed by the load shown below when its impedance is 56 +j15 ohms 21 A rms? Answer to three significant figures Homework Equations P=Irms^2*RThe Attempt at a Solution Converting 56 +j15 to polar form yields 57.9741 ohms @ 14.9951 degrees...

1. An oscilloscope is used to measure the voltage across two components using Channel A and Channel B. Deduce the RMS voltage of the signal measured by Channel A I just want to know what they mean by "deduce the RMS voltage" Do i need to calculate the Vrms?

Homework Statement Determine the rms value of v(t) = 15 + 10cos(20πt) Homework Equations Vrms = √(1/T*∫T0v2dt The Attempt at a Solution √(10*∫0.10[15+10cos(20πt)]2dt Unless, I'm much mistaken I should be able to plug the equation into the formula I have given above. I used...

so i have a question about calculating the RMS value of a fully rectified clamped sinusoid. Assumptions: The top of the waveform = U It is clamped at 0.5 U I can calculate the RMS value by adding the 3 components of the wave, ei. @ 0.5U ω = π/6 & 5π/6 which forms a block and two side...

Homework Statement A hypothetical atom is diatomic containing two identical atoms separated by an equilibrium distance. About this distance the atoms vibrate with the electric forces providing an effective spring constant of k = 4.0×10^−3 N/m. As the temperature of the sample is increased the...

Homework Statement Three lamps are connected in a household curcuit. Lamps 1 and 2 have 150W bulbs and lamp 3 has a 100W bulb. What is the Current (I) and Resistance (R) of each bulb? Homework Equations V=IR P = W/t = (V*q)t = V*I I= q/t V= W/q The Attempt at a Solution Lamp...

Homework Statement The ideal gas has a density of 2.4 kgm–3 at a pressure of 2.0 × 105 Pa and a temperature of 300 K.Find the root mean square speed of the gas atoms. Homework Equations p=(1/3)*(Nm/V)*v(squared) The Attempt at a Solution I tried to make v(squared) the subject...

I have an asymmetrical clipped repeating waveform and I want to be able to find the root mean square. The function is as follows, with r and b constants: y(t) = ((exp(sin(t)*b)-exp(-sin(t)*b*r))/(exp(sin(t)*b)+exp(-sin(t)*b)))*(1/b) This is pretty computationally heavy. What are some...

Homework Statement The length and radius of a perfect cylinder are measured with an RMS error of 1%. The RMS error of the inferred volume of the cylinder is.. ?Homework Equations V=∏r2h Hence dV/V=2dr/r+dh/h The Attempt at a Solution I took dr/r and dh/h as 1%. So got the final answer as...

How can we restrict the RMS speed of molecules to comply with relativity? They obviously can't go at or faster than the speed of light. If you are dealing with particles inside of very hot stars for example you may get very high erroneous speeds. v = \sqrt{\frac{3KT}{m}} How could...

Homework Statement The question is: The given answer is: Homework Equations The Attempt at a Solution I already got the "correct" answers. My question is, I used Vrms voltage and Irms current to solve the nodal analysis. Would it be incorrect to use Vpeak and Ipeam to solve the circuit...

If I have a wave that looks pretty much sinusoidal but the peak positive amplitide is greater than the peak negative applitude how do I calcualte the rms vlaue - is it still the peak positive amplitude divided by root 2? Thanks :)

Homework Statement Given an AC Voltage that varies in time according to the equation: v(t) = 100 sin(250t) (i) What is the frequency of this waveform? (ii) Calculate the time for one complete cycle of the voltage? (iii) Calculate the instantaneous value of the voltage at time =...

If I have multiple RMS voltage values over a day's time and I want to find the average - should I use RMS or arithmetic mean? I think I would use arithmetic mean because RMS is just to account for the +/- direction of voltage, but I'm looking for confirmation. Thanks!

Q: A single sinusoidal signal is found in a large amount of noise. If the RMS value of the noise is 0.5 volts and the SNR is 10 dB, what is the RMS amplitude of the sinusoid? I've related the question to the following equation: SNR=20log(singal/noise)dB My answer is 1.58 volts, BUT I'm...

Homework Statement Dust particles are 13.0 micrometers in diameter. They are pulverized rock, with ρ=2540 kg/m3 . If you treat dust as an ideal gas, what is the rms speed of a dust particle at 18.0 C? Homework Equations ρ=m/v V=4/3∏r2 vrms=√(3kT/m) The Attempt at a Solution...

Suppose at a test point in my circuit ,I need to measure rms voltage, how I should measure it with DMM?

Homework Statement I've spent the last hour trying to get this, and it's starting to drive me crazy! I'm not sure how to approach the waveform, as there are two forms? I'm guessing that the period in this case is 4 seconds, and they've included a second wave to reiterate that? Homework...

Homework Statement the power density of sunlight, at the earth, is roughly 1 kilowatt/meter^2. How large is the rms magnetic field strength?Homework Equations The Attempt at a Solution I tried using the equation for power density S = E(rms)^2=√(εμ), then substituting B(rms)/c for E(rms), and...

I know that some of our members have an interest in the loss of the Titanic in 1912. So I am posting a link to an article in/on Science Daily on the steel used in the Titanic. Also look at the related stories links on the right of the page for more related material. CB

I have a few questions I thought I'd post together instead of making separate threads, hope that's ok. They are more or less unrelated... 1. Are there 2 conceptual ideas that use the term "virtual work"? I am familiar with the one from intro level physics, but I read there is also one from...

Homework Statement The rms speed of the molecules in 1.1 g of hydrogen gas is 1800 m/s. 500 J of work are done to compress the gas while, in the same process, 2000 J of heat energy are transferred from the gas to the environment. Afterward, what is the rms speed of the molecules...

Homework Statement At 332 K and 1.28 x 10-2 atm, the density of a gas is 1.89 x 10-5 g/cm3. (a) Find vrms for the gas molecules. (b) Find the molar mass of the gas.Homework Equations Vrms=√(3RT/M) (RMS speed) PV=nRT (Ideal Gas Law) D=m/V (Density) M = m/n (Molar mass = mass/number of moles)...

Hi, In a system that uses a triac to switch mains voltage, how can one calculate the resultant peak voltage, RMS voltage and power for a given phase (conduction) angle e.g. 50°? Many thanks

Hi guys I'm trying to work out average and rms values of two different waveforms. One is a sinusoidal wave, the other a ramped trapezoid (I think that's right). The sinusoidal wave has a peak to peak voltage of 11v and the offset is alleged to be 9-15 = -6v. This is something I've been told...

rms velocity and compression. Please help! Homework Statement Explain why the rms velocity of a gas increases when it is adiabatically compressed. Homework Equations None The Attempt at a Solution I know that compressing a gas decreases the volume, but I don't know details on...

Homework Statement The rms speed of nitrogen molecules in air at some temperature is 493 m/s. What is the rms speed of hydrogen molecules in air at the same temperature? Homework Equations Vrms The Attempt at a Solution