Measuring Definition and 1000 Threads

  1. P

    How can I accurately measure the density and volume of microdroplets in oil?

    I need to measure the density of aqueous microdroplets in oil. My first idea was to obtain a set volume of the droplet-in-oil mixture and weigh it to obtain the density, weigh the same volume of oil without droplets, then estimate the volume of the droplets so I can work out their density...
  2. ChrisVer

    Probability of measuring muons is a particular setup

    Homework Statement You want to measure the momentum of muons with the help of a proportional chamber, that is a chamber that applies an electric field inside its cavity and produces a signal current when a charged particle passes through it. The probability of generation such a signal for a...
  3. Janus

    Insights Measuring How Many Days Are in a Year - Comments

    Janus submitted a new PF Insights post Measuring How Many Days Are in a Year Continue reading the Original PF Insights Post.
  4. A

    Measuring Qubits: Basics for Quantum Computing Beginners

    I am newly learning quantum computing and am confused about some concepts. Suppose your qbit is the electron of a hydrogen atom and its in the state α|0> + β|1> . As far as I can understand, this means that if you measure the qbit in |0>, |1> basis, you will get a ground state electron with the...
  5. O

    Radar antenna: measuring H or E?

    Hi there, Maybe this is a stupid question. Maybe not. I want to make a statement in my thesis that says that all radar antennas on satellites derive the EM field by: receiving the time-varying H field, and from the induced current derive the EM field. Am I correct in saying that? Or are there...
  6. Q

    Measuring Gravitational Redshift due to Galaxies without GR

    Hi guys. How do astrophysicists measure the redshift of electromagnetic waves from galaxies due to gravity without the use of General Relativity? If I can be more specific, how do astrophysicists know that the gravitational redshift of light emitted from some part of a galaxy or galaxy cluster...
  7. M

    Measuring distance a sound wave travels

    I would like to be able to measure the distance a sound wave travels. This is for a violin bridge and what I would like to do is apply a frequency corresponding to the frequency the string (196 hz for the g string) and determine the distance the wave traveled to get to the foot of the bridge...
  8. A

    Hall Effect Probe for Measuring Magnetic Field Strength

    Homework Statement In a probe that uses the Hall effect to measure magnetic fields, a 11-A current passes through a 1.33-cm-wide and 1.31-mm-thick strip of sodium metal. If the Hall emf is 2.42 μV, what is the magnitude of the magnetic field (take it perpendicular to the flat face of the...
  9. itssilva

    Creation and annihilation as measuring processes?

    From a purely theoretical standpoint, I'm quite comfortable with the concept of particle creation/annihilation, but, as a chemist, I cannot but feel that there's something missing in the way of interpretation, so I came up with the following 'explanation' of the phenomenon based on the measured...
  10. A

    Measuring a Coil of Wire With Ohmmeter and Balance

    Homework Statement A coil of fine copper wire has a resistance of 6.2 -Ω and a total mass is 14.4 g. What is the diameter d of the wire and what is its length L? (The density of copper is 8.96 g/cm3.) Hint Given: •Model the wire as a long cylinder of diameter d and length L. Write one...
  11. R

    Measuring redshift from type 1a supernova

    I know that you can measure redshift from stars by looking at the shift in there balmer lines or more generally there line absorption spectra and seeing how far these lines have shifted from actual balmer lines or line absorption spectra of the same elements on earth. But how would you...
  12. C

    Find the probability of measuring spin up an axis.

    Homework Statement Set |Ψ> = (1/√ 2) | ↑, z> + (eiθ / √ 2) | ↓, z>. Find the probability of measuring the spin component of sz to be up the z-axis. Find the probability of measuring the spin component of sx to be up the x axis. Homework Equations I'm not sure. The Attempt at a Solution I...
  13. A

    Operators for measuring superposition component distinctnes?

    Hello, I'm wondering, is it possible to define an operator that gives information about the "distinctness" of superposition components? As a simple example, imagine that we have two particles. Let |3> designate the state in which they are 3 meters apart, let |5> designate the state in which...
  14. Rodrigo Cesar

    Many Worlds Interpretation and act of measuring

    "We can’t make a measurement without influencing what we measure. before we look, there are only probabilities. When we open the box, they give way to a single actuality" It would be more like this, all the time, Until we look...
  15. J

    Measuring the electric field of the Earth

    Hi, I'm trying to measure the electric field of the Earth using a simple set up and would just like some opinions on the viability and practicality of this method. The set up is as follows, two parallel metal plates with one larger than the other, the larger one is placed over the smaller at a...
  16. gfd43tg

    Measuring x and ##p_{y}## precisely

    Homework Statement Homework EquationsThe Attempt at a Solution 1. $$ [\hat {x}, \hat {p}_{y}] = \hat {x}\hat {p}_{y} - \hat {p}_{y} \hat {x}$$ $$= \hat {x}(-i \hbar \frac {\partial f}{\partial y}) - (- i \hbar \frac {\partial (fx)}{\partial y}) $$ Since x is not a function of y, it can be...
  17. J

    Measuring the electron field emenating from the Earth

    Is there any portable/small device that will allow me to measure the strength of the electron field emanating from the Earth's surface, i.e., the ground at a given location? Thanks!
  18. K

    How can I measure rotational speed of a golf ball and projectiles?

    I'm planning on carrying out an investigation with a golf ball and projectiles. Is there any type of equipment/sensor that I can used to measure the rotational speed/angular velocity? I know a gun chronograph can be used to detect the velocity but what can I used to detect the angular velocity...
  19. J

    Measuring Light Years: How Far Is the Andromeda Galaxy?

    I was reading up on the Andromeda Galaxy and it was saying that it was 2.2 to 3 million light years away from earth. So my question is how do we measure how far it is in light years?
  20. seb7

    Measuring possible one-way anistropy of light speed

    wiki says "Experiments that attempted to directly probe the one-way speed of light independent of synchronization have been proposed, but none has succeeded in doing so" Here's a proposed experiment which I could not find any evidence of this being performed before.. Central light source...
  21. S

    Help with density measuring device

    Hi every one i hope someone can give me an idea how to achieve that. I am working for at school project, where i am trying to build a device that measure density of a multilayer object/enviroment. I am thinking to achieve that by measuring the axial force exerced while pushig the device inside...
  22. S

    Measuring properties of entangled photons

    I am not clear on the below, so any additional information would also be good. Let's say a pair of photons is entangled on 2 properties. When we measure on property A -- the values for property A (for both the entangled photons) becomes determinate/locked/fixed when we measure on property B...
  23. X

    Measuring Tape, Speed of Light & Time Dilation

    Had a thought the other day. If a spool of a measuring tape was on a vehicle traveling close to the speed of light away from the Earth, with the spool anchored to the Earth, due to time dilation, would an observer on the vehicle see the spool unraveling faster than the speed of light?
  24. C

    Measuring the resistance of a button

    I need to measure the resistance of a button on a car steering wheel, so my question is: how do I measure the resistance of a steering wheel button using a digital multimeter? I don't currently have the steering wheel installed yet, so can I measure the resistance of the buttons without the...
  25. litis

    Measuring Illuminance with Lux Meter - Can I Make Conclusions?

    Hi, I have a question. I have measured with lux meter the illuminance of the room. When in front of the photoelement I put my plastics - colourless, green, red, blue. The lux value had decreased in the same tendency - from the colourless to the smallest value of blue sample. So, can I made...
  26. K

    Measuring the One-Way Speed of Light: Roadblocks & Solutions

    Hi All, Recently I mentioned about a new method to measure the one-way speed of light. Quickly I was pointed to the existing roadblocks to such experiments, from members here and veteran professors in email. I have analyzed those roadblocks and putting here my understanding of the problems. To...
  27. E

    Build a LCD Flicker Meter Using Photodiode and Current Amp

    I need help in building a LCD flicker meter using photodiode and a current amplifier. The aim is measure the LCD pixels's flicker that can be detected by human eye so as to have a representation as electrical signal. This is to use it in cases where it's hard to judge if there is a flicker...
  28. C

    Measuring Radiation in a Closed System

    Suppose we have a closed system in which molecules cannot escape. Into this system we enter some radioactive molecules with \beta^+ decay. We know that the resulting daughter nuclide is also radioactive. We have some equations to describe the amount of parent nuclides and daughter nuclides...
  29. A

    Measuring Tension Between Train Carriages

    Im doing a prac for school that we have to create ourselves. My groups prac goes along the line of a train pulling two carriages. Our train is a LEGO NXT unit that runs at a constant velocity, no acceleration. We will have two force gauges between each carriage and the carriage and the train and...
  30. Tony Giaccone

    Measuring density with ultrasonics

    I'm interested in determining the density of a dough. I want to be able to continuously measure the density of the dough as it rises. My thought was to use an ultrasonic wave and measure the time it takes to reflect through the dough I would assume that as the dough ferments and the amount of...
  31. J

    Measuring a Qubit: Understanding Pauli Matrices

    I undertand that measuring a qubit's spin along a particular axis yields one of the eigenstates of the corresponding pauli matrices. I'm a little confused about what this type of measurement looks like mathematically. i.e how do you show the actual act of observing the qubits spin using the...
  32. rothran

    Measuring magnetic field of a solenoid relative to distance

    So, I recorded the result of a LabQuest 2 Vernier Magnetic Field Sensor on different points of a plane, with a solenoid in middle with a 5 amp current running through. I want to compare my results with theory, but have no idea what equation I'm supposed to be using. I assumed it was B = μ0ηI/r3...
  33. AdityaDev

    Measuring resistance using potentiometer

    Homework Statement Homework Equations For R, current I=E/R and for X, I=E/X... both are separate cases. The Attempt at a Solution [/B] Why does the balancing change? The potential difference across each resistor is E Itself right? I tried by assuming an arbitary internal resistance r...
  34. A

    Initial velocity by measuring negative acceleration?

    Hi, Quick Qustion : If an object is propelled through the air (e.g. a ball is thrown), once the ball has left the throwers hand it will immediatly start to have negative acceleration (at least in the x plane). If the negative acceleration is measured at the same point in time after the ball...
  35. psuedoben

    Astronomy: Measuring Radio Wave Distance from Universe

    when astronomers receive bursts of high energy radio waves from distant parts of the universe, how are they able to tell how far they have traveled? does it have to do with the wavelength?
  36. H

    Experimental Design - Measuring Force Vector on Cable

    Hi All, I'm trying to design an experiment for measuring force along a cable. The cable is will be held in a persons hand and the other end will be fixed to a transducer to measure the force of tension. In order to account for the multiple force vectors, I thought of using a gimbal table or...
  37. E

    Measuring Wavelength Homework: Middle of Lines or Book?

    Homework Statement Im not sure how to measure the wavelength when given this picture. Homework Equations The picture looks like this, it has two slits. The Attempt at a Solution My book says that the wavelength is 1 cm. When I measure from the middle of a white line to the middle of the...
  38. C

    Measuring Electric Fields w/Neon?

    Good day everyone! n00bie here. I did do a search before I posted this... found a lot of info, most of which I couldn't apply to what I am doing (because I wouldn't know how). I have something that I am working on that creates an electric field to alter certain chemical compounds. The distance...
  39. S

    How do we accurately measure distances in space?

    When we measure distances in space -- for example, when we say a star is 20 lightyears away -- are we measuring in a straight line ("as the crow flies"), or are we including the dips and curves in spacetime (that light travels along)? Thank you in advance?
  40. D

    What's the best device for measuring angles?

    << Moderator Note -- Dorea is an instructor asking about their physics lab >> The first experiment in our fundamental physics lab is "Measuring & Measurement errors". Currently we have four devices: - rule (0.5 mm) - Vernier Caliper (0.02 mm) - Micrometer (0.01 mm) - Spherometer We're seeking...
  41. oreo

    Pendulum measuring acceleration of car

    I came across this problem which says" A pendulum is hung by roof of a train having mass 1 kg . The train then accelerates and pendulum makes an angle with vertical. What is acceleration of train? " Is it equal to gsinθ?
  42. D

    Physically measuring forces of gun recoil

    I want to measure the forc e of an AR15 recoiling over time from a single shot. The gun cycles at about 900 rpm, so the recoil impulses should be over within 67 miliseconds. There are two different parts to the recoil impulse. Within less than a milisecond, there should be a large impulse that...
  43. S

    Measuring the Movement of the Stars

    I was wondering, since the Earth is constantly moving around the sun, the sun is moving around the milky way, and the milky way is moving through space (and for all I know the milky way might also be rotating around our local group, cluster, super cluster, etc.), how do we know how fast...
  44. Bassa

    Measuring Vectors: Force Exerted on Tripod Legs

    Homework Statement This is an example problem in my calculus textbook. I don't get how they relate the position vector to the force vector. I have taken a calculus based physics course and I don't remember establishing such relationship between the position and the force vectors. Note: I have...
  45. M

    Measuring quark colour operator

    What is the explicit 3x3 matrix operator which measures the colour of a quark? Essentially what I want to know is what is the analogue of ##S^z## for the measuring of spin.
  46. H

    Measuring impact force on rubber spacers

    I need to find the impact force that can be absorbed by these spacers as shown in the image. The spacers are radially distributed over the shell, and they are supposed to dampen any external impact loads to reduce the effective stress inside the inner shell. Since the FEA model is not showing...
  47. H

    Measuring power output by modified prony brake

    Hi guys I have problem, basically I want to measure the power output from a water wheel. so basically I measured the power output by connecting the pulley that attach on the shaft of the water wheel. then this pulley is connected to other pulley which sit on the shaft of the DC motor. this DC...
  48. M

    Probe/anemometer for measuring flow speed and direction?

    Hi, I'm trying to measure the steady state velocity field behind the wake of a bluff body in the wind tunnel. My uni is equipped with 4-hole cobra probes which is capable of receiving flow within a 45 degree cone of acceptance. As the base of a bluff body dominated with re-circulating flow...
  49. Lamdbaenergy

    Understanding Gravitational Red Shifting with a Solar-Mass Black Hole

    I've been searching over this and I don't quite get it yet. I just heard about this "z" parameter for gravitational red shifting and I thought it'd be fun to apply into the scenario of a solar-mass black hole. The equation I looked at was (1/(2GM/c^2r)^0.5) - 1 = z So, like, does the z parameter...
  50. N

    Measuring the current in an electrosurgical unit

    I have been trying to find an ammeter that can perform a specific task and failing miserably. I would appreciate any help I can get. and as you may soon notice, I have no engineering background. I am trying to find a non-invasive method for measuring the current generated in an electrosurgical...
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