Measure Definition and 1000 Threads

who was the first person to discover how to measure the wavelength of absorption lines in the solar or stellar spectra and what method was used?

Hi everyone, in this days i was seeing a little of Fourier series and transform, and i wondered if it was necessary to better understand before the measure and Lebesgue integral before studying it. Or it's not necessary?

I have to build a digital peak flow meter. I ve read that you can measure the volume metric flow rate using a differential pressure sensor. H ow do i go about doing so. The peak flow meter will be used to measure asthma.

Homework Statement Somebody knows an experiment to measure directly frequency of de Broglie waves?

For the Blackbody Spectrum, there are two versions of the formula, one for wavelength and the other one for frequency: The peak intensities for both occur at different wavelengths (or frequencies).How do scientists measure the spectral radiance of blackbodies? Are there TWO types of...

Whats the relation between degree and time, is there any historical answer.

How come when an ammeter is placed in parallel with a resistor that is connected to a battery, the circuit is considered incorrect + "safe," whereas an ammeter connected in parallel with the whole battery is considered incorrect + dangerous? My guess is that it has something to do with the...

Hi, I'm a noob when is comes to these kinds of measurements on a spectrum analyzer. Take for example two LDOs: 1. http://www.analog.com/media/en/technical-documentation/data-sheets/ADM7154.pdf 2. http://www.ti.com/lit/ds/symlink/lp5907.pdf (see figure 17) They claim...

Unlike Ohmic resistors the resistance of a semiconductor decreases with temperature...or not. Can a fragment chipped off a diode or some random IC be used to measure this with a multi meter??

Hello Aren't all irrational numbers having an infinitely long decimal component? If so, how can any measure of a physical quantity be irrational? the decimal component is infinitely long..but the magnitude of the physical quantity surely isnt?

I want to build a telescope and want to know which type of lense is better suit for this. Please anyone help...

I'm wanting to know if I can and if so how to measure the voltage of two AA batteries whilst they are in a device with the device turned on. This device is a vibrating toothbrush so if anyone could help with an answer, it would help teremendously with my science project as I am testing the...

I would like to preface this by stating that I am not very well-versed in cosmology or astrophysics, but I've been thinking: I understand the idea of parallax, both in the sense of human eyes measuring distances to nearby objects and in the sense of telescopes on Earth (or in orbit) measuring...

Hello all; Sorry if my questions are stupid or weird, but I'm still a beginner in quantum mechanics. So please be patient with me! I'm reading shankar text of quantum mechanics,and I reached the part related to momentum operator and the momentum wave function in position basis. He derived that...

We have a Renishaw inVia confocal Raman microscope. Currently I am using it to study photoluminescence. I have a very thin film with certain thickness (e.g. 60nm and 120nm). It turns out that they (60nm and 120nm) have different emission spectra. Here comes the question: Can I divide the...

What does this formula measure? c= \sqrt{2EY/\pi} This topic is from fracture mechanics. Does this formula tell you how much stress is required to cause the crack to increase?

Hi All, I'm searching for the possible method to determine organic coating thickness cover on steel tole was plated by thin zinc layer. Additionally, I also want to measure thickness zinc plating layer in between these layers (coating on top & steel on bottom) without destructing them. Please...

Hi, I'm doing a high school physics project that involves a small toy car tied to a bottle filled with pressurized air. By removing a certain thumb tack on the bottle, an orifice is exposed which expels a stream of air that acts as a force of thrust. I'm going to measure AND theoretically...

I have found a book from my father epoch of undergraduate student in Physics. It was apperently Physics 101, and was written with a typewriter and the formulae with pen. I have gone straight to Special Relativity section and, to my dismay, and even if all formulae were indeed correct, the...

Hello world, I'm currently in my last year of high school and only just getting interested into quantum physics, still learning new things every day. I was wondering if there's a way to measure the specific amplitude of a light wave(Or electromagnetic wave) and what this says about the wave...

what are the equations to measure attenuation, frequency, amplitude of a stress wave propagation of metal rod or plate which is immersed in water or fluid?

Let \mathbb{S}^n be a simplex in \mathbb{R}^{n+1}, so \mathbb{S}^{n}=\{x\in\mathbb{R}^{n+1}|\sum{}x_{i}=1\}. Let D be a difference measure on \mathbb{S}^{n} with D(x,x)=0 and x=y for D(x,y)=0. D is also smooth, so differentiable as much as we need. Let (R) be a convexity requirement for D...

This idea has been bothering me for a while, it started when I thought that if there was an infinite amount of space inside of an inch. ( or even any measurement in the physical world ) Then I thought that maybe that's not a fair argument on the basis that quantum theory says planks length "h"...

Please anyone explain me from where we measure current or we apply ammeter in a pn junction diode to measure current

I've been trying to teach myself the path integral formulation of quantum field theory and there's a point that's really bugging me: why is the integration measure ##\mathcal{D}\phi(x)## invariant under shifts in the field of the form $$\phi(x)\rightarrow\tilde{\phi}(x)=\phi(x)+\int...

The energy of an incident charged particle refers to its kinetic energy. What does the potential barrier energy refer to qualitatively? EDIT: Is it just in reference to the "potential barrier" in the classical sense? where if the particle has less than the energy V, then it doesn't go through...

Homework Statement Homework EquationsThe Attempt at a Solution This is how I drew it (in pencil) , but there should be a rheostat connected in series with the power supply, why?i can already calculate the resistance straight away by V/I

Hi I'm confused about what an accelerometer actually measures. I downloaded an app that reads out the data of the accelerometer in my phone in all three dimensions. If I lay it flat on a table, it says something around 9.81 in the z direction and something around zero in the x and y directions...

1) When a FET is completely on, the voltage drop across the drain-source is ideally 0. This means that when completely on, V_{ds}<V_{gs}. Why doesn't the FET go into ohmic/triode mode when V_{ds} dips below V_{gs} ? 2) Why are we measuring these voltages relative to the source (for a standard...

A block of aluminium is charged by a van-Graff generator and isolated in space, the goal is to measure the amount of electric charge in this block or at least a part of it. What equipment should be used and how? Note: the purpose is to investigate how does the geometry of the block affect the...

Homework Statement What's the difference in using GPS Data vs. using Magnetic anomalies, fracture zones, hot spots to analyze plate motion? Homework EquationsThe Attempt at a Solution Seems like a question with a direct answer. What's the difference between the two? I am struggling to find...

Just as a fore-note, I understand this question may be hard to answer, and I'm sorry if I slip into philosophy. We humans can understand time on our scale, but we cannot necessarily comprehend events that occur say on a quantum level, they seem to go to fast. Now my question that arises is that...

I have two signals (time series) shown in the plot below. Just by looking at the figure, we can see that the two main peaks of both signals are very closely aligned (correlated), however the red signal has additional features elsewhere which don't match the blue curve. I am looking for some...

Hi everyone Given the definition of ##C_{l}##, ##C_{l}=\frac{1}{2l+1} \sum a_{l,m} Y_{l,m}##, I was wondering how it is possible to measure the ##C_{l}##s in practice. How does one compute this quantity, having a map of the temperature anisotropies of the CMB?

Hello, So, I know quarks are confined in baryons. In a proton, there are "3" quarks, but the sum of their masses is not the mass of the proton. This implies a major fraction of the proton mass comes from interactions. My question is, how then do they measure quark u and d masses? And...

Hi I'm studying electron-muon scattering and now considering the Lorentz invariant integration measure. The textbook introduced it, which use dirac delta function to show that d3p/E is a Lorentz scalar. I understood it but I wanted to find other way and tried like this: I need a hint on the...

Hi! I'd just please like to know the most efficient way to conduct my experiment. See, my research question is "for what angle is horizontal speed the fastest?" We all know that the steeper a hill is, the faster an object accelerates. Obviously a 90 degree angle won't do much. I will try to...

I have a formal lab due, and my idea is to use a bifilar pendulum, model its period using experimental data, and examine the effect of the length of the strings on the amplitude of the period. For anyone unfamiliar with it, here is a picture of the pendulum. This is how I plan on setting up my...

This is a bit of a random project I am looking into. Recently a product was released called the beer bug. It measures the density of beer by tracking the weight of a submerged buoy. They calculate change in density based on changed in weight and then calculate % alcohol (ABV) from that...

Hi there i wonder how can i measure the plasma temperature ? and what is magnetic field have the impact to plasma or not? Thank you all.

If we devise a physical system and perform an observation of some physical quantity, how can we infer that this quantity is related to the eigenvalues of the momentum operator -ih d/dx ? Another way to look at it. Suppose you were handed the theory of quantum mechanics and that you already had...

Hi, just curious. Sorry I am trying to get a handle on this , will try to make it more precise: I am trying to see if the following has a categorical parallel/counterpart. Consider the case of measure spaces (X,S,m) : X any space, S a sigma algebra, m a measure and that of metric spaces (Y,d)...

I'm trying to measure now much non redundant (actual) information my file contains. Some call this the amount of entropy. Of course there is the standard p(x) log{p(x)}, but I think that Shannon was only considering it from the point of view of transmitting though a channel. Hence the formula...

Hello everyone. I'm pretty new here, and I kinda joined this forum just to post this question. I have read many books on physics and cosmology, and although I have no scholastic training in it currently, I plan to study physics in college. Anyway, I get all sorts of ideas in my head, but this...

Hello Forum, I know a little bit about how the oscilloscope works: an electron beam hits the scope screen and traces the waveform. Once the beam reaches the right side of the screen it zaps back to start tracing again. Is it possible that while the beam returns to the lefthand side of the...

Hello, I'm looking for some ideas as to how I can get the position of a beacon/actuator to within 0.1mm in a cube 10m x 10m x 10m. I need to take a reading off an instrument at every point within this volume, with a displacement of 0.1mm between readings. The lidar systems I've looked at are...

Dear All: I have recently encountered a small question regarding the determination of the degree of circular polarization of light. In an optical experiment, we are trying to create a circular polarized light beam by passing a HeNe-laser through a linear polarizer and a quarter wave plate (in...

I posted this picture in another thread but I now have a specific question for the capactance measurement between both transducers (the middle C). How can I measure the capacitance of this using an LCR meter. Where should the leads be put and what are some averages of a capacitance I should be...

I've just started self-studying measure theory by reading Pugh's Mathematical Analysis. I'm trying to understand his argument for why the exclusion of a zero set does not change the outer measure: $m^*(E\setminus Z)=m^*(E)$: (Pugh's arugment): Let $Z$ be a zero set, $E\subseteq\mathbb{R}$, and...

A = 46 degrees b = 8 I don't even know how to start this and I'm really confused. I've already labeled A and b but I really have no clue on how to continue. .-. Can someone please explain this very carefully to me and use simple terms? I've been trying to do this problem and I was told that I...