Measuring Definition and 962 Threads

In electrodynamics, the gauge potentials are not directly measureable, but components of the field strength tensors, which are the electric and magnetic fields are. But why are the electric and magnetic fields, the components of the curl of something not-measureable (the gauge fields)...

Hi, When we talk about neutrino oscillations, the discussion is always about the phase that a particular flavour eigenstate picks up with time. The phase is usually partly geometric and partly dynamic. I have a question about this. How do we measure the phase experimentally? What is the...

If I moved in the rest frame of a solar neutrino would I still measure neutrino oscillations? Thank you for any help!

Suppose a rocket is traveling almost at the speed of light...but relativity says he will still measure the speed of light 3*10^8...if a beam of light is sent at the time the rocket started...if the beam of light and the rocket both travel the same distance, let 2 light minutes, then what will...

Hi there all I'm looking to measure current in 3 phase cables, and would like some advice on any current clamp models you'd like to recommend. However, I'm not entirely certain on the method as well; I've used current clamps before on single phase cables, and I'm aware that you need to clamp...

I am not 100% certain this is the best place for this. Moderators, if you think a different board would be better, please relocate this. Anyway... I am wanting to measure the peak temperatures of my combustions of hydrogen. I got to thinking, "If I am using air as the source of oxygen, then...

Hi, I am working on this project that has to involve physics, chemistry and biology. The chemists in my group will be performing an experiment to measure the enthalpy of combustion of three different fuels: alcohol, diesel and petrol. My task as a physicist is to, using their results...

Hi, I was wondering how I would go about measuring the electrical charge of an aerosol (A sodium chloride aerosol generated using a compressed air type nebulizer and dried using compressed at approximately 100 l/min flow) I have seen Faraday cup used for such measurement but was hoping for...

I asked this in another thread but I may have been off topic.. I'm not quite sure which thread to ask in.. I was wondering if it is okay to say that you can measure an inch in any direction but you can only measure time in one direction. And if, in the same vein, is it okay to say that you...

How can the bond angle in a molecules are measured ? The methods used to measure the angles and length b/w bonds.

Homework Statement You are to design, build and test a method to accurately measure the mass of an object. You cannot directly weigh the object but must use experimental data to determine your result. You cannot build any type of spring balance or beam balance. You are to determine your method...

Hello. Some years ago I came across an animated illustration of relativity, housed in what seems to be a classic use of a bouncing light within a spaceship. (Similar to that found in http://galileoandeinstein.physics.virginia.edu/lectures/srelwhat.html.) My education in physics is limited to...

Hello, I had to measure the resistance between different sets of bridge deck reinforcement steel bars using a Wavetek HD110T multimeter and a wire. The values varied between 1.9 to 2.8 ohms. When I measured the resistance of the wire itself, it came out to be 2.1 ohm. I could not...

Hi all! I tried to make an inductor. Naturally, I am not sure about it's inductance value. I made an LC series circuit on a bread board. I am using a oscilloscope and an a function generator to find the value of L during the resonant frequency. Channel one goes from function generator...

Hi all, First of all, thank u for ur time and sorry about my english. I have measured a loudspeaker's Sound Pressure Level from a distance of 1 m. At the same time, I've measured, with a accelerometer, the displacement, velocity and acceleration of the loudspeaker's diaphragm. I've found...

Just wondering if anyone can explain to me why it is thought necessary to say that consciousness (an observer) is necessary to account for certain things in Quantum Physics (e.g. for the collapse of the wavefunction), rather than just say that a measuring device (with or without a conscious...

Homework Statement This is an example from Gasiorowicz's Quantum Physics. "Example 3-1" is a particle in an infinite potential-well, but that should not matter. Homework Equations The Attempt at a Solution Why is P(-2) (which I suppose is the probability that the eigenvalue -2 is...

Hello, our teacher told us that how could we find the gravitational force of the Earth, and i wanted to do it with falling objects (Only option i got, no pendulums). Does anyone have an idea what is a free-fall apparatus? I wanted to measure it just with a cronometer, but i need more precise...

hi the venous pressure is typically about 5mm Hg describe a method to measure this pressure

Hi. I was wondering if someone can provide me with some advice on the proper way for measuring the optical power of a pulsed laser system? My optional methods are: - Photodiode detector: measuring average power - Oscilliscope with optic-electric converter...

The acceleration of gravity can be measured by throwing an object upward and measuring the time that it takes to pass two given points in both directions. Show that the time it takes the object to pass a horizontal line A in both directions is Ta, and the time to pass a second line B in both...

My company installed a number of balancing valves (Tour & Andersson, STAD) in a central heating system. These valves are used to measure the flow (in this case water). According to the valve's specs it should be installed with a certain distance of straight pipe both before and after the valve...

Hi, Homework Statement I am trying to determine the size of a molecule..by doing the oil drop experiment where we drop a tiny droplet of oil on water covered with a thin layer of powder...and then make calculations based on the diameter of the circle... the droplet forms in oil. The Attempt...

Homework Statement Derive an equation how one can calculate concentration by measuring pressure change in a known volume. Known data: Pressure change dp/dt in a known volume V, volumetric flow rate F, total pressure p and temperature T. Homework Equations Probably ideal gas law...

Hi. I have been given the task to measure the speed of sound in air. The materials available are: 1. Microphone 2. Signal Generator 3. Amplifier 4. Digital Oscilloscope I have looked through google and the simplest exp involves a loudspeaker as well. However I don't have one...

Hi, Is there a way or reasonably priced equipment out there that can measure the energy levels of transients in electrical circuits? Any help would be appriciated!

Greetings, I have a problem that's been bugging me for a few days now. I've asked electrical engineers, students and graduates, and I can't seem to find a clear-cut answer to these questions. THE SCENARIO One piece of copper wire has one end connceted to a terminal from a multimeter...

Just a very conceptual question about measuring momentum of a particle: first off, when we measure the position of a particles by say, firing a photon at it, its wave function collapses to a spike at the point where the particles was seen.. If we measure the momentum of a particle, its wave...

Hello, I am trying to help a student set up an experiment in which he needs to measure the force of a punch. Any suggestions on what equipment/sensor I can use to do this? Thanks! Jessie

Homework Statement For the pendulum or spring and mass system at your station measure the period with a stopwatch Homework Equations The Attempt at a Solution So a period of a pendulum is when it returns to its original position after passing equilibrium twice. So I would...

Hello Can anyone explain to me what measuring quadratures are in relation to homodyne detection? Thanks

Hello, I have a question related to coordinate transform. If this is not the right section please feel free to move this thread. My problem is the following: I have a positioning system to move an antenna, that allows me to perform scans according to a great circle coordinate system. Check...

Have to find the probability of measureing the ground-state energy of a particle. -in infinite potential well 0<x< a has wave-function \psi (x,0) = Ax(a-x) where a is the (known) length of the well, and the norm. const. A has already been found. The eigenvalues of the hamiltonian in...

I have read the parallax method of determining large distances and i do understand it. I agree it is easy to find the distance of the basis(distance between two observation points) but how do they measure the parallax angle?

Hello all, I'm a bit new to to the forum, but from the posts I've read, I can say that this is a fantastic site. I have a fish tank with some live plants in it, and I add CO2 to the water by putting some sugar, water and yeast in a two liter bottle and pumping the gas into the water. Worked...

Hello all. I'm am a first time poster but a long time visitor. I am having a little trouble that I was hoping someone far wiser and more knowledgeable than myself might be able to help with. I've been using MCNP to investigate criticality in a simple geometry consisting of a central natural...

I hear a lot about astronomers using type IA supernovae to accurately measure large scale distances over billions of light years to do things like measure the rate of expansion of the universe. I doubt that the calculation of this distance is simply based on the inverse square law. So my...

would a 1.5 volt electronic device that measures capacitance to turn on or off a regulator that controls water flow affect a defibrillator or pacemaker? Another way to ask this, A kitchen faucet that is touch sensitive would be safe or not safe for a heart patient who has defibrillator and...

Homework Statement This is a lab problem and basically I am supposed to explore the properties of a capacitor. Here is the question that confused me

For the MMX, the speed of light is measured isotropically at c in free space regardless of the frame, so gives a null result. To another frame of observation, light still travels isotropically at c while the apparatus is length contracted by sqrt(1 - (v/c)^2) in the line of motion, whereby a...

An apparatus has these properties when measuring a polarized photon: -whenever a linearly polarized photon at angle \vartheta enters apparatus, it displays "2" -whenever a linearly polarized photon at angle \frac{pi}{2}+\vartheta enters apparatus, it displays "3" -for all other polarizations...

Homework Statement I want to calculate the surface area, mapped with points. For starters, I've mapped the edge of a circle with 200 points, then created a few more circles, each with 200 points. The problem is I get different surface areas for the same size circles. The only difference...

If there are 2 objects emitting light to each other and the light fills the spacetime between them and then that spacetime expands the waveform becomes stretched. However, if the middle of the spacetime between the 2 objects has yet to have light enter it from either object and that spacetime...

If we were to measure the speed of light as the scientists in the 1800s did (such as Foucault and Fizeau), without knowing the relationship between speed of light and its wavelength and frequency, would it be possible to do so using only simple apparatuses like mirrors and low powered motors and...

Homework Statement How do you measure the output of a voltage divider with real voltmeters that have effective resistances Homework Equations The Attempt at a Solution I know that for an ideal voltmeter (one with infinite resistance), the voltage divider is R2/(R1+R2), but I...

Hi guys, I have problems with a high-school assignment: Homework Statement http://img843.imageshack.us/img843/3748/74698735.png An experimenter tries to determine the speed of sound in air. He tries to lower and elevate the water in the tube at the same time as he hits on the fork, until...

hi there, I have been studying the postulates of QM in shankar book, and in the part it explains how measurement affects the system, it talks alittle about the expectation value and the uncertainty. then I came across this problem which I don't get. it gives three L(in x direcion), L(in y...

In the double slit experiment - what exactly is the measuring device? .. the have to measure witch slit the photon went trough - how do they do it? - measuring anything means interacting with it. Changing it, really. So, isn't it obvious that interacting with the photon in any way will...

Ca. 1996 a colleague bragged to me about an undergraduate lab he'd worked out where they did a high-precision measurement of g (I think he claimed 3 sig figs) using an index card, a pin, and a stopwatch. He didn't tell me any details. I've long since lost contact with him, but I was thinking...

Hi, I'm a civil engineering student in a summer internship at the moment but I've come across a mechanical issue. We want to buy or build a very accurate (+- 100mm) odometer for a large truck. We have a Survmaster precision odometer in there but it's only accurate to +- 1.0m which isn't good...