Measurement Definition and 1000 Threads

Homework Statement If x = (7.2\pm0.6) m, determine the value of ln x with its associated uncertainty. (Ans is 1.97 \pm 0.08) Homework Equations A = k{B^m}{\rm{ }} \Rightarrow {\rm{ }}\frac{{\Delta A}}{A} = m\frac{{\Delta B}}{B} (perhaps?) The Attempt at a Solution i tried to...

First of all I wanted that I am not a physicist. I have an introductory knowledge gained from college, tv, news, magazines etc. So that's why came here with this question. I thought maybe you could help me with. So the question is simple. As technology has advanced we are able to measure...

What is the most accurate way of measuring the amount of calories a person has burned in a certain time period?

Suppose we prepare a system in some properly normalized superposition of the spherical harmonics: A|11> + B|10> + C|1-1>. One of the fundamental results of quantum mechanics is that, if we measure L_z, we will collapse the state of the system onto an eigenstate of the eigenvalue we measure. My...

I want to measure level of water at two positions in tank. How to measure it? |-----|_> here & | ----|_ >here |____| Fig. Tank when water level reach to certain levels(1,2) o/p voltage should be generated. I hav to connect it to 24 V DC PLC i/p. I need simple and easy solution. PLZ help me.

Just thought I would get a couple of opinions from you guys on something I find truly amazing. In Brian Greene's Fabric of the Cosmos he explains how the delayed quantum measurement experiment works. A single photon has already passed through a beam splitter and made the 'choice' of whether...

hello. I am working to understand and design a UV sanitization device. What is a good resource to learn about irradiance and its relation to distance from a surface. Secondly, in real life, how is irradiance measured? Given a surface area, I would need to specify bulbs of certain...

What is meant by a "partial measurement" or "partial measurement in the Bell basis?" More specifically, I'm trying to read the Wikipedia article on quantum teleportation, but I don't know what is meant when they say Alice performs a partial measurement on her qubits.

Homework Statement Knowing the given equations, k is equal to a measurement where J(t) implies some local coupling between the observer and observed system. If a field is considered to collapse J(t), how would the two manifest into a single expression. Homework Equations...

Say we have an electron in a position eigenstate \delta(P-x) at point P at time t_0 . We also have a detector at another point Q. At t_0 , the probability of the detector registering the electron is zero. After a certain time T , the time evolution of the wave function generates a...

If the current, voltage and power are measured at the terminals of a device containing only resistance and inductive reactance, how many values of R and X can be determined from just 1 A.C. measurement? (P.S. This is not homework but an elec engineer who has been stumped)

hi. as a non-physicist reading physicsbokks i have a problem understanding how, in richard feynmans words, "time itself", is measured. feynman seems to move from clock-measurement to "time"-measurement without a justification. as tsr clairly states time-dilation i have a problem of...

Maybe this counts as computational physics, or statistics I don't know where this topic belongs. Ok so I have this nice high quality Thermodynamic measurement data and I have to start the "data raping" for results. Let's call the series A(t), and B(t) and I have a few more. So for different...

Hi, I am doing an experiment to investigate the propagation loss in some nanophotonics structures. The laser light is coupled to the input of the DUT chip via a tapered lensed fiber and the output of the chip is go through a objective then a photodetector. The chip is design for...

Can someone point me to a good comparison of the various forums of temperature measurement? (Thermocouples, Thermistors, IR, etc), I'm interested in finding out more about : relative cost, accuracy, size, output type, any other constraints on the technology.

Reflection is not considered to be a measurement. Reflection, like using lenses is considered to be a time-reversible process. It is not a measurement and it does not erase the coherence (interference pattern) Here is what I don't understand What happens to the momentum of the photon? The...

Homework Statement I have no idea how to calculate this: Calculate the uncertainity (limit error) when you convert minutes to hours: Minutes____Hours__ 10.0 0.16 20.0 0.33 30.0 0.5 Homework Equations They've given me like Time Elapsed...

Homework Statement To measure the activity of a rock thought to be radioactive, a physicist puts the rock beside a detector and counts 225 particles in 10 minutes. To check for background, she removes the rock and then records 90 particles in 6 minutes. She converts both these answers into...

Do quantum logic gates perform measurements? (collapse the wavefunction) For example: If I apply a cNOT gate to a pair of cubits with wavefunction 1/\sqrt{2} |10> + 1/\sqrt{2} |00> what would I expect as the result? 1/\sqrt{2} |11> + 1/\sqrt{2} |00> ? or 1|11> or 1|00> or...

Hello, I would like to know how to select the radius of a pitot static tube to test the air flow in side a circular tube?? Thanks in advence.

if there are two identical systems,in quantum mechanics(or any other theorem),according to schrodinger equation, they will evolve congruously.but from the instant of measuring,the evolution seems disobey its original principle----i mean the evolutions are not congruously any more. is that mean...

Description of method: The rotor's mass is constant so when it accelerates in a given wind, it does so with an acceleration = torque/mass. This acceleration will depend essentially on wind speed. If tests are carried out in the open with non-turbulent winds it is possible by using a tachometer...

I want to measure the temperature of a metal surface surrounded by glass with a near infrared pyrometer(1.45 micron to 1.7 micron). I am not sure the influence of the glass on the measuremental accuracy. You know the infrared radiation may be absorbed by the glass to make uncertainty. Please...

Homework Statement The Shadow cast by a vertical pillar in Alexandria at noon during the summer solstice is found to be 1/8 the height of the pillar. The distance between Alexandria and Syene is 1/8 the Earth's radius. Is there a geometric connection between these two 1-to-8 ratios...

[b]1. I recently had a lab on free falling and have all the data and percentage amounts from the data sheet, and Position vs. Time. I'm having a problem creating the slope for the velocity vs. Time. Do I use two different points or just one point? I used to different tangent lines...

I know that σ is the symbol typically used for standard deviation, but what does the use of σ mean in these contexts? ex. 1: "[our fancy new instrument] ... allows for the identification of > 500 sources at greater than 10-sigma" ex. 2: "These estimates assume ... a 1σ polarization...

Measurement is probably the most important act when we attempt to understand our universe; without measurement we would have no information at all. The problem is including measurements in our theory leads to complications which our difficult to describe. I will outline a couple of the problems...

Has anyone have experience in measuring C-V curves of MOS capacitors using HP LCR meter. I am in very urgent need. Please help me

Hello, first of all sorry for my bad english it is not my mother tongue I am new to the uncertainty and significant figures concept and I have measured some things, I want to write the results using them. The length of my table is 273,3 cm. The instrumental uncertainty is ± 0,3 cm, and I...

Homework Statement Lets say m1 = 80 +- 0.1 g and m2 = 60 +- 0.2g and p = 1.0 g/cm^3 +- 0.1 g/cm^3 I want to solve for V and V = (m1-m2)/p What would the uncertainty on this be? When you subtract the two masses, it becomes 20 +- 0.3g. You divide that by 1g/cm^3 +- 0.1 g/cm^3. 0.3...

I have a question that has been bugging me lately. How is it that you determine the total error of a measurement? For example, if we are trying to measure the flow rate of water coming out of a hose. We let the water flowing through the hose fill a graduated cylinder and measure the time it...

-------------------------------------------------------------------------------- Ok so if two particles are entangled and I choose to measure particle A, then the entanglement is finished. But what if I measure both A and B with photons of the exact same energy; is there now a new...

how to determine static characteristic of rotational measurement device

Dear folks The case is this... to measure the color transmittance through a coating on a transparent sheet... and the values are in L, x, y [thought there should be a "y" but its not in the report]... Can anybody shed some light on how to interpret L, x, y in this report ? Thanks !

Homework Statement reading shankar he develops the measurement of angular momentum by discussing rotation state vectors in 3-D by the angle-and-axis parameterization so he creates these generators of rotation matrices and says these are what we use to measure angular momentum in analogy to...

Hi, I am on a placement year with an engineering company who design tools for the nuclear industry. One of the tasks I have been given looks at what linear measurement devices can be used in a radioactive environment? I havn't been able to find much and was wondering if anyone could point me in...

Hi everyone In my attempt to understand the details of Stern Gerlach experiments and measurment issues in quantum mechanics, I have come to believe that there is a lot to be learned from some of the basic thought experiments like interference and Stern Gerlach described in books...

Homework Statement In an experiment to measure the speed of light using the apparatus of Fizeau, the distance between light source and mirror was 11.45 km and the wheel had 720 notches. The experimentally determined value of c was 2.889 x 10^8 m/s. Calculate the minimum angular speed of the...

First of all, this is not a homework question. This was a question on a test I wrote on friday for which I cannot find the information in any texts. The following: "pressure exerted by a water column measured in feet of water or occasionally inches of water" is a good definition of...

Homework Statement "If the photon has a short wavelength, and therefore a large momentum, the position can be measured accurately. But the photon will be scattered in a random direction, transferring a large and uncertain amount of momentum to the electron" Homework Equations I am unsure...

Homework Statement Homework Equations theta = length / radius The Attempt at a Solution I came across this question in Fundamentals of Physics (Resnick / Halliday / Walker), in the chapter Measurement. Now I understand that this is a simple geometry-based question. Basically, the '38...

I just gave my Physics exam paper... and i want ask few questions and confirm if they are right... Question asked to draw diagrams for longitudinal wave and transverse waves... I drew transverse waves correctly... but did i correctly drew the longitudinal waves? i made a wave like...

Someone repeated the Cavendish experiment at about 0 K? My question: the gravity force is costant when mass is near 0 Kelvin? It is possible a weakening of G, a 'transition phase'?

It is known that a particle in a one dimensional box with walls at (-a/2, +a/2) has energy probabilities: P(E1) = 1/3, P(E2) = 1/3, P(E,3) = 1/3, P(En) = 0 for all other n. If the parity of the state is measured and +1 is found, what can you say about the value of the measurement of E sometime...

Homework Statement Concentration of acetylcholine (ACh) determined from pH change after hydrolysis. Sample incubated with acetylcholinesterase is quatitatively converted to choline + acetic acid which then dissociates to acetate + H+. A 15mL solution has unknown amount of ACh with pH 7.65, and...

[SOLVED] "Particle in a Box" Measurement scenario Problem statement: Measurement of the position of a particle in a 1D well with walls at x=0 and x=L finds the value at x=L/2. Show that in a subsequent measurement, the particle will be in any odd eigenstate with equal probability...

Homework Statement Have two Greenberger-Horne-Zeilinger (GHZ) states of qubits A, B, C and D, E, F as follows: \mid GHZ \rangle_{ABC} = \frac{1}{\sqrt{2}} \left( \mid 0 \rangle_{A}\mid 0 \rangle_{B}\mid 0 \rangle_{C} + \mid 1 \rangle_{A}\mid 1 \rangle_{B}\mid 1 \rangle_{C}\right) and...

Homework Statement I am in such a situation, where we are trying to measure the characteristics of a stepping motor in order to verify its operational characteristics. I have tried measuring the motor's torque in many ways but I am having trouble following the company maker's method given...

What is the specific heat capacity of HCl when given the following information: Volume: 50mL Initial Temp: 20 *C Final Temp: 26* C What is the heat measurement in Joules as well? What is the specific heat capacity of HCl when given the following information: Volume: 100mL Initial Temp...

I read on NIST CODATA that electron mass is a fundamental constant. I take from this that proton mass is not fundamental. I also read it is possible that proton-electron mass ratio may vary. So I wonder how proton mass is measured or derived. I have no training in physics, however in studying a...