What is Rms: Definition and 208 Discussions

Roxar RMS is a reservoir characterization and modeling software suite. It is primarily designed for use in the oil and gas industry, helping engineers gather data from a wide variety of sources to efficiently build reliable reservoirs.

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1. A Exploring Orbital Velocity vs RMS of Eddy Velocities

Is there a difference between the orbital velocity of an eddy and the root mean square of the velocity fluctuations? I'm particularly interested in understanding the eddy turnover time of the largest eddies in a turbulent flow, which is given by the characteristic eddy size and the...
2. I Is RMS speed dependent on pressure?

As it is clear from the formula for r.m.s speed ,it is only dependent of temperture for a particular gas,I think the answer should be "No change happens".But I wonder whether there is more insight to this.And is my assumption true?
3. Question on RMS Mean Free Path

lambda (rms)= v(rms) * t(rms) -- 1 Now I assume here that t(rms)=1/(√2*n*π*d^2*v(rms)) But this cancels the v(rms) term when used in eq (1) so the mean free path and the RMS free path would actually be the same (even later on when used in the aforementioned Survival Equation) I would like to...
4. Engineering Power and RMS Value of a Signal

I need to calculate the power and RMS value of some equations. The problem is, I found two methods to do that and don't know which is the right method. I have few equations to find the power and RMS value, but here is one equation. $$x( t) \ =\ 7\cos\left( 20t+\frac{\pi }{2}\right),$$ Method...
5. Creating a stable 5V DC supply out of 6 V (RMS) AC

I need to create a 5 V stable DC supply out of 6 V AC from a transformer. By "stable", I mean that I do not want the ripples in the voltage that one gets from the output of a full-wave bridge rectifier. I have to feed this to two ATmega 8A μCs. I am going to create the following circuit: 6 V...
6. Fick's Law, time and RMS question

This is an experiment on a dilute isotopic mixture of helium gas. A spherical vessel of diameter 1 m is first filled with 4He gas to one atmosphere pressure. Then a small amount of 3He gas is introduced through a valve on one side of the vessel. Make a rough estimate of how long one must wait...
7. B What is the RMS value in this context?

In this text they are saying that rms value is square root of average value of i² but i am not able to relate this thing to equations they have given. It feels to me that the equations tell something different from the text. From text I interpret that if we add each and every value of i² from 0...
8. Maxwell distributions and average, RMS, and most probable speeds

What I know about a Maxwell distribution is that an area under the distribution on an interval gives the fraction of the molecules with speeds on that interval. My first question is what does Maxwell's distribution represent? It is given by the formula ##P(v) = 4\pi \left(\frac{M}{2\pi...
9. Engineering How to find RMS, and Peak Voltages of this signal?

Hi all! I have a complex waveform, something like what I have attached, and I need to extract the RMS and Peak Voltage from this. However, this signal can and will change after a number of cycles on a certain setting. So, this means the period and duration of pulse can change and so can the...
10. A 50 kW load operates from a 60 Hz 10 kV rms line with a power factor of 60% lagging -- Determine the capacitance that must be placed in parallel

Please can you have a look at the file at point me in the right direction if I'm wrong. Thank you
11. Find the RMS current drawn from the 240 Vrms supply

My first idea was to find the total impedance of the circuit, but I think viewing the two parallel resistors as one resistor of 0.5 Ohm isn't the correct way? I don't know how to simply this series / parallel circuit further to find Z total. Then I tried to use Kirchhoff's law to the loop on...
12. RMS velocity of molecules in a mixture

I know that for a single monoatomic gas with RMS velocity ##v_{rms}## , $$\frac 1 2mv_{rms}^2 = \frac 3 2k_bT$$ where ##m## is mass of a single molecule, ##k_b## is Boltzmann constant and ##T## is temperature of the gas. For a mixture of gas, I know that the average kinetic energy after mixing...
13. I RMS vs. RSS for uncertainty

Hi, the following statement comes from a document of Keysight spectrum analyzer: The sources of uncertainty can be considered independent variables, so it is likely that some errors will be positive while others will be negative. Therefore, a common practice is to calculate the root sum of...
14. Why RMS for the average voltage in AC current?

We write rms formula as $$v_{rms}=\sqrt\frac{\int_a^b[f(x)]^2dx}{|b-a|}$$ I know if we take arithmetic mean average voltage will be 0. So we want all voltage values to be positive. Why don't we do that: $$V_{average}=\frac{\int_a^b\sqrt{[f(x)]^2}dx}{|b-a|}$$ That's first what I did...
15. RMS and DC Value Displays of Waveforms on LTspice

I hope I am posting this in correct forum section. I just downloaded LTspice for my Power Electronics course. Does anyone know if the software can display the DC component of a waveform such as found by determining the Fourier series of a waveform?
16. Given RMS Speed, Find Temperature

mass of N2 = 28 * 1.67e-27 kg not sure if this is the right one - just googled it triple covalent bond N2 radii = 54e-12 m I tried to first find the rms speed: v = x/t = 50 * 54e-12 / 3 m/s Then I solved for T (in K): [50 * 54e-12 / 3]^2 * [28 * 1.67e-27] / [3 * 1.38e-23] = 9.14e-22 K
17. Charge and current, RMS or aritmethic mean?

I'm calculating current through a resistor by measuring a single current pulse, integrating it and multiplying it with its frequency. This would correspond to calculating an arithmetic mean. I also tried calculating RMS of this waveform, using GNU Octave, and was a bit surprised by the...
18. How to calculate triac angle to set desired RMS voltage

Hi, I would like to implement voltage regulator based on microcontroller + triac. I am able to calculate source RMS voltage by sampling signal using ADC, but don't know how to calculate triac angle to set desired RMS voltage. For example i have 250v source RMS voltage and i need to calculate...
19. Third Order Intercept - Use Peaks or RMS?

Hi, I have a tough or straight forward question... please can someone share knowledge I have two sine waves at different frequencies, my fundamental frequencies, and they are summed together to produce a signal. This signal is put through a non linear transfer curve of an amplifier, which is...
20. RMS or Average Current Homework - Tips & Tricks

Homework Statement [/B]Homework Equations I calculated for RMS current. The Attempt at a Solution How to know whether they've asked RMS or Average current? Isn't Output always RMS? Average value is of no use anyways.
21. Is it maximum voltage or RMS voltage

Homework Statement Homework Equations I drew phasors and got the answer. Angle between V and I is 60 degrees. Cosine of 60 is 0.5. Then I multiplied V and I and divided it by 2.The Attempt at a Solution I got answer 62.5. But I'm not sure if values of V and I given are rms values or maximum...
22. Finding the surface RMS error using Zernike coefficients

Hello, I am given 200,000 surface points in terms of x,y and z coordinates which is supposed to represent a circular paraboloid antenna reflector surface and another 200,000 points when the antenna surface is subjected to wind loads and gravity. I am supposed to find the surface RMS error of...
23. Calculate the RMS current of an ac circuit

Homework Statement : [/B] calculate rms value of current i= 3+ 4 sin(ωt+π/3)Homework Equations : [/B] Irms2=(∫0T [I(t)]2dt)/TThe Attempt at a Solution: I tried to integrate but I'm getting a T term.
24. Simple RMS velocity question, what's wrong with my answer?

Find the rms speed for an argon atom if 1.5 mol of the gas is confined to a 5.6 liter container at a pressure of 5.5 atm. PV = nRT RT = PV/n v_RMS = \sqrt (3RT/M) = \sqrt (3PV/nM) = \sqrt ((3 * (5.5atm * 101.325kPA/atm) * (5.6 * 10^-3 m^3) / (1.5 mol * 39.948 * 10^-3) = 12.5 m/s However...
25. RMS speed in kinetic energy equation for gas

I have been pondering. Why is it that we use the rms speed in the equation Ek = 1/2 m vrms2, as opposed to just the mean speed2
26. Solving for RMS current of a resistor, help?

Homework Statement A resistor connected across an AC power supply has a current given by I=(1.35A)cos(300t) when connected to a power supply with emf 120 V rms. Find the RMS current. Homework Equations IRMS=Imax/√2 The Attempt at a Solution IRMS=Imax/√2 IRMS=0.477 A INCORRECT Not exactly sure...
27. Calculate uncertainty in pressure, temperature and time?

Homework Statement [/B] After doing a lab on air compressors, we were asked to calculate Error in Pressure, Temperature and time measurements taken (all at 30 second intervals). We took pressure and temperature values at time = 0,30,60,90,120,150 and 180 seconds. We repeated the experiment 5...
28. Why does RMS power produce the same heat as the equivalent DC power?

Hello. I was browsing online to answer the question to why RMS voltage is used as opposed to the average voltage (and by average I mean over half a period, roughly 0.64V_peak), and the explanation I found was that the RMS voltage would produce the same heat as equivalent DC through a resistor...
29. Calculating RMS Speed of Helium & Oxygen Gas at 260K

Homework Statement (introduction course of university physics)[/B] A 5.0- liter gas tank holds 1.7 moles of monatomic helium (He) and 1.10 mole of diatomic oxygen (O2), at a temperature of 260 K. The ATOMIC masses of helium and oxygen are 4.0 g/mol and 16.0 g/mol, respectively. What is the...
30. Sunlight, Intensity, electric field RMS

Homework Statement Estimate the rms electric field in the sunlight that hits Uranus, knowing that the Earth receives about 1350 W/m2 and that Uranus is 19.2 times farther away from the Sun (on average) than is the Earth. Homework Equations I=cεoErms2 E=V/d The Attempt at a Solution Eearth=V/d...
31. Calculating Vrms: Homework Equations & Solutions Explained

Homework Statement imgur link: https://i.imgur.com/9jozS67.png Homework Equations The Attempt at a Solution [/B] Shouldn't I use V_{rms} = \sqrt{\frac{1}{T}\int_T v^2 dt}? Which would be \sqrt{\frac{100}{2\pi}\int_0^{2\pi/100}(20+60cos(100t))^2dt} This equals \approx 79.88 V The...
32. RMS value secondary voltage electronic halogen transformer

I am trying to derive a scaling factor for an analog voltmeter for the purpose of measuring the secondary voltage of an electronic halogen transformer (EHT). http://www.ledbenchmark.com/faq/Transformers-Output-and-Compatibility.html The output voltage of these things is a "high frequency"...
33. RMS Current through RLC combination ciruit

Homework Statement Referencing the attached picture: a) Show that the RMS current in the 1 kΩ resistor is 6.5mA. b) If the AC voltage source was replaced by a battery, what would the current in the resistor be? Homework Equations V = IR Z = √(R^2 + X^2) The Attempt at a Solution To begin, I...
34. How can RMS current be phasor?

If RMS current is equal to the value of the direct current that would produce the same power dissipation in a resistive load, how can it be phasor?
35. RMS of square wave and alternating currents

Homework Statement Find the value of the RMS current in the following cases: (a) a sinusoidally varying current with a peak value of 4.0 A, (b) a square wave current which has a constant value of 4.0 A for the first 3 ms and -2.4 A for the next 2 ms of each 5 ms cycle, (c) an alternating...
36. Is the circuit breaker amperage the rms amperage

The circuit breakers of my house say that they are 15a (the majority of them). The rms voltage is 120v for the outlets, and so the peak voltage is about 170v. I was wondering, if I hypthetically connected the terminals together with a 10 ohm resistor, would the breaker trip? I don't know if the...
37. Find the RMS value of current I

Homework Statement In the network of sinusoidal current, as shown in the figure, the current i2 is phase delayed for the angle of 3π/4 behind the current i. In the moments in which the current i2 is minimal, current value of current i1 is sqrt(2) A. This value is two times lower than the...
38. Effect of density on rms speed in ideal gas eqn

Homework Statement Homework Equations 1) PV = nRT 2 )## P = ⅓ ρ<c^2> ## 3) KE ∝ T The Attempt at a Solution According to the second equation above, density is inversely proportional to root mean square speed at constant pressure, but the answer states that the root mean square speed depends...
39. Root Mean Square: What It Is & Why It Matters in Electrical Engineering

What is the root mean squad (RMS) of a signal (or wave) and why is it important for electrical engineering? How do you Find it? What is it used for? Thank You All
40. Rms velocity of electron in free space?

Homework Statement How many orders of magnitude smaller is the average drift velocity of a hole than the RMS thermal velocity of an electron moving in free space? (Use the law of equipartition to find the RMS thermal velocity of a free electron.) This is the last part of the problem, I have...
41. Find the rms electric field strength of a given EM wave

Hi, I was able to correctly calculate the answer to part 1 below but the answer to part 2 is incorrect and I cannot see the error of my ways... any help gratefully received. 1. Homework Statement An electromagnetic wave has an intensity of 127 W/m2. 1) Find its rms electric field strength...
42. Calculate the rms speed of one nitrogen molecule at 27 Celcius

Homework Statement Calculate the rms speed of one nitrogen molecule at 27 Celcius Homework Equations sqrt(v^2) = sqrt((3kT)/(m)) The Attempt at a Solution sqrt(v^2) = sqrt((3kT)/(m)) k = 8.62*10^-5 eV/K T = 300 K 3kT = 0.078 eV m = 14 g/mol m = 0.014 kg/mol 3kT/m = 0.078 eV/0.014 kg/mol =...
43. A quick question on RMS speed of gas molecules

Homework Statement As attached. Homework EquationsThe Attempt at a Solution I chose A but the correct answer is E.(Actually I thought both of them were correct) From the graph provided,it is clear that the turning point corresponds to the largest proportion of molecules,so is the corresponding...
44. What is the RMS of this current?

Homework Statement Find the average current. The problem and given solution are in Untitled.png. Homework Equations RMS = sqrt((1/T)(integral of x^2 dt from 0 to T)) The Attempt at a Solution From time 0 to 1, the equation describing current is 10t^2. From time 1 to 2, the equation...
45. What is the RMS magnetic field of light

Homework Statement A window, 1.0m by 1.0m receives 27J of energy, from sunlight, in one minute. What is the Rms magnetic field of the light striking the window. Homework Equations E = cB I = (ErmsBrms) / μo The Attempt at a Solution Not sure if those equations are right when solving this...
46. Average and rms values of a given signal

Homework Statement I am in an Intro to EE class and we were given a homework assignment including the following question: Find the average and rms values of the signal: x(t)=3cos(7ωt)+4 I have formulas for average power and rms but they include V & I, however the signal was given as x(t). I...
47. How to Calculate RMS Current in a Simple Circuit

Homework Statement Sorry for what will likely be considered a noob question but I've been stuck on it for a while and its only at the start of my assignment :( Simple circuit Vac = 50Sin200πt, R1 = 40Ω Calculate the value of the RMS current Homework Equations Vt = Vmax sin2πft = Vmax sinωt...
48. Electrical meter and efficiency question

Q1. I know a DMM will anticipate a sineusoidal supply, thus there can be problems with spiky supplies. Even if you have a true RMS meter, it it's a spikey supply, non-sineusoidal, you still can't calculate the peak of a spiky supply? Does a DMM measure the peak, then calculate from THAT the...
49. Understanding Diffusion: The Relationship Between RMS and Fick's 2nd Law

Hello everyone, I have a question concerning the following: There is a relationship for diffusion concerning the RMS: <x^2>= 2\cdot D \cdot T for one dimension and there is also Fick's 2nd Law. When does the above formula apply? What I don't understand is that in the RMS formula there is...
50. RMS and average current triangle

I would like to know how to find RMS and average current of a triangle? i searched the web. but it focus from 0. which i know. but my waveform is different from the internet. i have attached the waveform.. Maximum = 2.5 , Minimum = 1.8 i need to find out the RMS and average current