Rms Definition and 208 Threads

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

Homework Statement This is the given function: Homework Equations The RMS equation goes like this: \sqrt(\frac{\int(f(t)^2 dt)}{b - a}) The Attempt at a Solution The first part of the exercise was to find the mean value. This is A/4. The RMS value should be higher...

We've just learned about kinetic theory and gases and my teacher showed us the rms speed. He himself doesn't know why its called the rms speed, or how it originated and I was curious to find out myself. Why go through all the trouble when you could just say the average speed? If anyone could...

Homework Statement c) Find T, the temperature at which He gas molecules have an rms speed of v = 733 m/s. Homework Equations Vrms = √(3kT/m) The Attempt at a Solution (Vrms2m)/3k = T (7332*.004kg)/(3*1.381e-23J/k) = T 5.187e25k = T Any help with figuring out what I did wrong...

Homework Statement I know the rms of a half wave is half the peak value. But the peak value is not given to me. Instead, the V(t) function of 4cos(20pi(x)) is given. Also the period T = 100ms Homework Equations vrms = vpeak/2 But the peak is not given! The Attempt at a Solution...

I've a theoretical circuit that resembles an on-off switch with a duty cycle of 50%. The voltage input to the circuit is a constant 5v. The current drawn from the source is 1A when switch is ON and 0A when OFF. What is the Vrms and Irms? From what I know: Vrms for constant 5v is 5v. Irms...

I need help, and can't find anywhere how to calculate the .707 value using calculus. The value used when calculating Vrms =Vp*.707, i need to know how to calculate the .707. Any help would be great, Thanks! Scott

Homework Statement Hello, I was wondering if anyone could confirm my work for the following graph: I'm supposed to find the rms for 1 complete cycle (0, 10ms) The time constant is 1ms. Charging phase, v=1-e^(-t/1ms)=1-e^(-1000t) discharging phase, v=e^(-1000t) The Attempt at a...

Homework Statement i_1=10+20sin(377t+(\pi /6)) i_2=-30 i_3=10+10sin(100t-(\pi/4)) i_4=10sin(377t) i_T=\sum _i i_i What I am wondering is how you go about calculating the average value for the linear combination of all three functions. Also, how would one calculate the rms for...

Homework Statement What is the meaning of rms power? Is it useful?Homework Equations Prms=Pmax / √2The Attempt at a Solution I' m not very sure about the equation I write above. Is that correct? I am learning about AC. I find that the average current is the same as Irms and average voltage is...

Homework Statement [PLAIN]http://img16.imageshack.us/img16/7396/oscf.jpg What is the RMS voltage of the top wave? Homework Equations RMS... root mean square The Attempt at a Solution If I'm right, the peak voltage is 1 V (gotten from 2 * 500mV). Square of 1 is 1. And there are 4...

[PLAIN]http://img16.imageshack.us/img16/7396/oscf.jpg What is the RMS voltage of the top wave? I'm new to EE, and trying to learn this stuff, so help would be great!

Homework Statement Find the acceleration of gravity. Using the trendline equation of Force v. hanging mass, find the RMS uncertainty for the force. Trend line equation: y = 9.8968x - 0.0342 R² = 0.9493 Data Values: Hanging mass is the first number. Force is the second number...

General enquiries (template may not be suitable) - When the question provides value of AC voltage amplitude, is this the same value of peak voltage? - Also, in current waveform, when do we use peak current and rms current? - In ohm's law equations we use rms current, so in the current...

Homework Statement A 2000 turn solenoid of length 1.50 m and diameter 5.00 cm has a dc resistance of 3.0. It is connected to a 50 Hz, 40.0 Volt (rms) ac supply. Find the rms current in the solenoidHomework Equations Vind = L di/dt Vind = Induced EMF Ohm's Law V-Vind = IR L = (4pi x 10^-7)n^2 Al...

Homework Statement Hi, here is the problem I'm having trouble with: The rms value of the magnitude of the magnetic field in an electromagnetic wave is Brms = 0.137 T. The intensity of this wave is approximately... Homework Equations E = cB I = (ErmsBrms) / \mu0 The Attempt at a...

Hello, In the chapter on thermal noise it says that the spectral distribution per Ohm of resistance is a certain shape (constant till a certain f and then ~ 1/f²). What is this expression? Is it physically the power dissipitating in the resistor, at least a certain part of it...

Find total kinetic energy and root mean square velocity of the molecules of 10 liters of helium gas at an equilibrium pressure of 105 N m−2. Density of helium is 0.1786 gram/liter. I am having trouble with the question, I know: K=(Nm<v^2>)/2 PV=(Nm <v^2>)/3 but I am not sure how to...

Homework Statement In outer space the density of matter is about one atom per cm^3, mainly hydrogen atoms , and the temperature is about 2.7 K. Calculate the rms speed of these hydrogen atoms, and the pressure (in atmospheres). Homework Equations.5mv^2 = 3/2 KT The Attempt...

Homework Statement In outer space the density of matter is about one atom per cm^3, mainly hydrogen atoms , and the temperature is about 2.7 K. Calculate the rms speed of these hydrogen atoms, and the pressure (in atmospheres). Homework EquationsPV = NkT The Attempt at a...

Hello, can someone please explain what exactly is meant when it is said that some measurement is accurate to some value RMS? Eg, "suppose that we have a bucketful of nominally 100-ohm resistors, accurate to 1 percent RMS" or, "we shall use an ohmmeter with an accuracy of 3 ohms RMS...

Find the root-mean-square electric field (averaged over all frequencies) at a point in space 1 meter from a 40-watt light bulb. The emitted power: P = 40 W R = 1 m Intensity: S = P/(4\piR2) S = (c/4\pi)<E2> Erms = (<E2>)1/2 Now I will set the two equal and solve for <E2>...

Homework Statement An AC power supply with a peak volatge output of 200 volts, operating at 60 Hz, is connected to a 53 microFurad capacitor A) what is the difference in phase angle between the applied voltage and the current B) what is the rms current in the circuit C) what is...

A lot of questions: http://img846.imageshack.us/img846/4963/capture3jpg.jpg http://img861.imageshack.us/i/captureh.jpg/ Find i2 Solution: http://img847.imageshack.us/img847/3773/capture2g.jpg Sorry for image spamming, i thought i should give you exact numbers and all so u can...

Homework Statement So this is the final section of a problem I had posted earlier, and I'm kinda stumped again. The rms speed of the molecules in 1.2 g of hydrogen gas is 1800 m/s. 300 J of work are done to compress the gas while, in the same process, 1500 J of heat energy are transferred...

Homework Statement A generator with an rms voltage of 130V is connected in series to a resistor 3.65k\Omega and a capacitor 3.00\muF. Using the frequency found in part A (47.5Hz), find the average power consumed by this circuit. \phi = 17degrees Homework Equations Latex isn't...

Homework Statement A container is filled with a mixture of nitrogen and oxygen. What is the ratio of the rms speed of oxygen molecules to that of nitrogen molecules? (Molar mass of oxygen=32gmol-1; molar mass of nitrogen=28gmol-1). Homework Equations v2=(v12+v22+...+vN2)/N The...

My friends and I have been working on this for the last two hours and we're still on 1a. I'm desperate and I'm going anywhere for help. If anyone's taken/is good at modern physics then please help. We're still in a physics review thing so it's not as complicated. The question is "Using the...

I'm in my second year of a physics degree and my QM lecturer showed us how to calculate the RMS around the expectation of an operator by considering the E of a system in equal superposition of two energy eigenstates u_1 and u_2. He then says "This gives some measure of how far off we would be...

I never really understood why using the Root Mean Square of negative data is the preferred method of finding the average of the data as opposed to taking the absolute value of the data and taking the average (arithmetic mean) of that. The example that recently made me wonder about this is...

How does a True RMS analog voltmeter work (if it exists)? (I am not interested about digital Sampling methods) I have heard about 'absurd' methods like heating up a coil through the sample voltage and using a thermocouple driven simple DC voltmeter to give the reading proportional to the...

Homework Statement A 39.5 uF capacitor is connected to a 47.0 ohm resistor and a generator whose rms output is 25.2 V at 60.0 Hz. Calculate the rms current in the circuit. (also asks for voltage drop across resistor, capacitor and the phase angle for the circuit, but I mostly want to get...

[b]1. find the rms value of i=1/3sin3t between t=0 and t=1/10 [b]2. not sure of the method or the formula i may need [b]3. Any help appreciated

Homework Statement The output voltage of an a.c. generator is \emph{V}=\emph{NBA}\omegasin(\omegat). When the voltage is connected across an inductor, the rms current in the inductor is found to be 10mA. What will Be the rms current if the rotating speed of the coil inside the generator is...

Homework Statement The speed of a group of molecules are 2, 3 , ... 11 km/sec. find the average speed of the group and also find the R.M>S speed of the group ? Homework Equations The Attempt at a Solution by summation of all 2+3+4+... 11 / 11 . is it right ... and how i find RMS...

I have a 4072x22x10 matrix. I am trying to calculate the RMS of the 4072x22 matrix but am unable to do so. The worst case scenario would be to individually calculate the RMS value of each element but that would require a number of loops and I don't want to do so. Is there any easier way to get...

Hi folks, this might be a stupid question, I don't know, but I'm working on a design for a wind-driven alternator, and while calculating the rms value of the output ac, which is maximum 18Hz AC, sinusoidal, it suddenly struck me that the rms value of a low-frequency wave must surely be much...

Can someone explain to me in the context of optoelectronic devices what rms linewidth means?? For example the rms linewidth of a particular laser is 0.1nm. What does that mean? and what implications does this have on a communications system using that laser? Thanks

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Homework Statement If V= Sin[wt] where w = angular velocity t is time in radians How do you find RMS Voltage Does RMS voltage depend on angular velocity of sin wave? Homework Equations The Attempt at a Solution i integrated from 0 to PI radians and left with a sin...

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I'm trying to calculate the RMS for square, triangle and sine waves. I can easily do the integrtion for sine waves and for square waves by looking at the graphic and getting the areas. It doesn't seem as easy for triangle waves since its squared form looks much more complicated and I'm not...

Homework Statement The rms speed of molecules in a gas at 20.0°C is to be increased by 1.4 percent. To what temperature must it be raised? k = 1.38E-23 (Boltzmann's Constant) Ratio in speed: 1.014 : 1 Ratio in Volume: 1.014² = 1.0282 : 1 T1 = 20°C = 293°K The Volume of 1 mol of an ideal...

Homework Statement ac voltage v=sinx Homework Equations how do you prove that rms voltage is 0.707v using integration The Attempt at a Solution

1. A canister containing 150kg of an ideal gas has a volume of 8 m^3. If the gas exerts a pressure of 5*10^5 Pa, what's the rms speed of the modecules? I can't get the temperature of the canister...

Hi everyone, I have a question maybe one of you can help me out. I have been working on a solid state tesla coil made with mosfets and a sg3524 PWM chip, I have got it working and am in the process of adding a current limiter to it (Mosfets can get expensive). The current limiter works with a...

1. Uranium has two naturally occurring isotopes. 238U has a natural abundance of 99.3% and 235U has an abundance of 0.7%. It is the rarer 235U that is needed for nuclear reactors. The isotopes are separated by forming uranium hexafluoride, which is a gas, then allowing it to diffuse through a...

Homework Statement A beam of polarized light has an average intensity of 13.2 W/m2 and is sent through a polarizer. The transmission axis makes an angle of 27.5° with respect to the direction of polarization. Determine the rms value of the electric field of the transmitted beam...

Does the rms speed of a gas change when the no of molecules are lowered, isothermally? I know that at same temp, avg kinetic energy remains the same. m1 (v1)2 = m2 (v2)2 If m2 = m1/2, v22 = 2 v12 Is this correct?

Hello all, I would like to know what is the theory behind the formula of the rms speed, Vrms = root(3rt/M). Thank you