Measuring Definition and 962 Threads

The measurement of g appears to be somewhat limited in extent. You either have simple pendulum experiments that yield something like 10 +- 0.5 or so m/s^2 or - at the other extreme - very expensive gravimeters which will measure to a few ppb. Not much in between. However an educationally useful...

I have a question that I feel I cannot find enough on. We just did a practical in Physics class where we used a laser light shined on a single hair strand in order to create a diffraction pattern and use formulae to determine the hair's width. Because of Babinet's principle, the hair managed to...

My hope is to explore [the existence of] dynamic correlation of plant tissue (leaves to start with) electrical resistance to stimuli. I've heretofore conducted experimentation reasonably sure enough of the techniques and materials I'll need that I've never posted for such advice in a public...

When we look at those pictures of colliding particles in particle colliders, we see a large collection of curves and lines radiating out from the point of collision, representing the new particles which have been created. So two questions about this: 1) Why are these acting like particles in...

Today's Astronomy Picture of the Day discusses a method for determining the distance to a galaxy that I had not seen before. https://apod.nasa.gov/apod/ap170707.html For a far away galaxy, the distance to M106 is well-known in part because it can be directly measured by tracking this galaxy's...

Homework Statement A small generator of 5kW, 240V and a constant frequency is used to light up 35 bulbs in parallel, each one has (240 V, 60 W) printed on it. Calculate the resistance of each light bulb. Homework EquationsThe Attempt at a Solution Attempt 1[/B] Pw = V²/R ----> R = V²/Pw...

In the wave equation## \frac {\partial^2 \psi} {\partial x^2}=\frac{1}{v^2}\frac{\partial^2 \psi}{\partial t^2}\tag{1}##, v is the speed of the wave propagation. With respect to which reference frame is this speed measured( in general)?

I have to check whether my circuit producing a burst of 500V in CRO. How can I check whether CRO is capable of handling this high voltage? I have heard about HV probe, how to check the probe that I have is of HV type?

First of all, it's not intended to be a philosophical question, but rather a physical one. So, what can we say about time? Maybe, it's a human way of measuring how things evolve in space? Suppose there are a room with objects within it, where nothing ever happens. There's no need to talk about...

Homework Statement Figure 2.2 (attached) shows a graph of distance against time squared for a ball bearing falling through the air. In accordance with s = ut + 1/2 a t^2 the graph should be a straight line through the origin. Explain how a systematic error in s and t could lead to the graph not...

Hello, on the internet, there are various methods on measuring the inductance. For example, http://www.dos4ever.com/inductor/inductor.html and https://electronics.stackexchange.com/questions/182116/whats-the-easy-way-to-measure-a-dc-hobby-motors-inductance If I want to measure the inductance...

When we try to measure shorter and shorter distances. eventually we have to put in so much energy into such a small space that it creates a black holes, thus makes it impossible see inside. So there is a limitation to how small distances we can measure. Exacly how does this happen? Why do we...

Hi, I want to measure the motor resistance of a gear DC motor by experimentation and Ohm's Law. Should I measure the current without the gear head, with the gear head, stall current (with gear head) or stall current (without gear head)? I am trying to obtain values for Equation 4 in...

If i have the momentum of the particle, could I measure their energy ? I'm talking about particles in a beam, they are moving in a relativistic speed.

If I measured the velocity of an electron what happens to its position? Does it collapse into a specific position or is it still uncertain? Here's a thought experiment... we measure the velocity of an electron and then send it through the double slit at the same time. Does the electron still...

https://link.springer.com/chapter/10.1007/978-3-540-39664-2_1 http://iopscience.iop.org/article/10.1088/0031-8949/1988/T22/016/pdf In these two experiments done back in the 80's, electrons were trapped inside a penning trap for long periods of time. They were measuring the ratio of the magnetic...

Since pitot tubes measure total pressure from the flow ramming into the total pressure hole, could I use any thin piece of pipe facing the flow (given that it's smooth on the inside) to measure total pressure? Trying to think of ways not to use my pitot tube to measure the total pressure of a...

I have a technical question, for research purposes. I have LED that we probe in AC mode. To measure the applied voltage in AC and the light-response in AC is no problem. However I would like to measure the current going through the device as well and I would like to link it to an oscilloscope...

Sorry if this is a dupe: An astronaut is in a windowless, sensorless starship that is drifting in an unknown location in space. There is an accelerometer aboard which reads zero. The astronaut turns on his ideal linear propulsion engine for one second, losing a negligible amount of propellant...

Hi guys, I have a set of 2-D data in excel, an X and Y column. The X column ranges from ±200 and the Y column is a Gaussian distribution ranging from about 6 to 12. In total there are about 500 data points. I need to normalize the data so that the Y column values have endpoints at 0 for X=±200...

Homework Statement Determine the heat loss per square meter of skin surface due to convection at -40degreeC in moderate wind (0.5 m/s, Kc=10 Kcal/m2-hr-degreeC), assuming that the skin temperature is 26degreeC. Homework Equations hcov= 10.45 - v + 10√v ΔQ/Δt = A hconv (Tskin - Tair) The...

Hello, I got two series connected coils which I exited with 15 V AC. I got EMF between the space in the field and I measured it with gaussmeter saying 200 µT. I want to know the freqency of that generated electromagnetic field? Does anyone know how to do it? Is there any Equation for it...

Hey there! This thread started off as a question regarding the impact of blindness on the wave function collapse, ended up thinking of an alteration to the double slit experiment that I think could yield some interesting results. So! Say the double slit experiment is run with measuring devices...

Hello! First time posting here. I'm studying the IB and need to complete my required experimental write-up. I am looking to replicate the well-known experiment that finds the value of g by investigating the relationship between period and length of string for a simple pendulum. 1. Homework...

Hi. I'm curious about how a PSA (polariser-sample-analyser) ellipsometer works, especifically the detector bit. In an ellipsomenter, light passes through a polariser which puts it into a known polarisation state. After that it hits a sample (which may be an interface, a surface or a thin film)...

Hi, So I have this situation, I'm totally inexperienced with anything electricity. But as faith has it sometimes, suddenly I need a device that would be able to measure the electrical conductivity of a thin film. Is there anyone who could guide me what would be the essential parts of a system...

Homework Statement You are required to set up a light source, an object grid, a converging lens and a screen so that a quantitative investigation of object and image distances can be performed. Tabulate corresponding object and image distances (p and p' respectively). Also tabulate values of...

When we are measuring the spin of the electron in the experiment, we choose the spin property as its eigen state for the measurement. The eigen vectors corresponding to these states could be time dependent. Can we still break the problem into solving time independent Schrodinger Equation and...

Homework Statement I need to use the overlap rule to find the probability that a measurement of a particle's energy at time t=0 will give the ground state E0 The normalized wave functions I have are...

Could you use a water u-gauge (manometer), zeroed and with one side of the u-gauge plugged and the other open to air, to show an increase or decrease in barometric pressure after a period of time (e.g. 2 hours)? The idea is that you trap some air at the starting atmospheric pressure on one side...

Hi everyone ! I'm currently working on a project for which I need to measure the advancing contact angle of a liquid on a solid, specifically the advancing contact angle of a molten thermoplastic on carbon fibers. My understanding is that there is a difference between dynamic contact angles...

Can we say a piece of marble is in an eigenstate of the observable position? If you try to measure other observable like momentum, the other eigenstate of position is supposed to be erased. So how come we can't cause a marble to vanish by measuring momentum. Would you know other objects...

Homework Statement A particle has the wavefunction ##\psi(\theta, \phi) = \sqrt{\frac{5}{2\pi}}\sin(\theta)cos(\frac{\theta}{2})^2\cos(\phi)## What are the possible outcomes of measuring ##L^2## and ##L_z##? And the relative probabilities of each outcome? Homework EquationsThe Attempt at a...

I am trying to measure the charge(or voltage) of a positively charged sphere by touching it with a non- calibrated electroscope. I am getting consistent results in the separation(or angle) between the metal leaves, but I don´t know how to calculate the voltage between the leaves from there. I...

Homework Statement The operator for the momentum of a particle in 1D is ##\hat{p}_x = -i\hbar\frac{d}{dx}## has the eigenfunction ##\psi(x) = e^{ikx}##. The Schrodinger equation for a free particle in 1D is ##\frac{-\hbar^2}{2m}\frac{d^2\psi}{dx^2} = E\psi## Which has the solution ##\psi(x) =...

Homework Statement Hi, I'm doing a biology course online and I'm specifically learning biochemistry right now. I'm having a problem with the following question related to one type of passive transport in a cell: this being osmosis. This question relates to measuing osmosis (isotonic...

Using only a compass and a ruler, how can we measure the diameter of a hollow sphere?

Homework Statement Figure 2: Homework EquationsThe Attempt at a Solution 3.2) I made an equation for the input voltage and input current Vi = Vs*(Zi)/(Zi+Rs+Rm) Ii = Vs/(Zi+Rs+Rm) I am a bit confused about what voltages V1 and V2 are measuring, and what do they mean by using the phase ...

Homework Statement I was doing this experiment: http://practicalphysics.org/shm-cantilever.html I'm interested in the derivation of the result ω^2 = Exy^3 / 4*M*L^3. I tried to think where it comes from. How do we even start to derive k from the equation mg = KS where S is the delta in the...

Hi is there any device or experiment, which could measure Earth spin vector and magnitude, centrifugal/centripetal forces, so i could derive from it, where is west and east , what's the vector of Earth rotation and what's my lattitude. Im assuming these forces and effects has to be...

Hello all, I will be using a photodiode to measure optical power. The photodiode will convert this power into a current. The optical power will pulse rapidly in 15 ns periods with a 5 ns on-time (at full amplitude) and a 1 ns rise and fall time. I am looking for an analog averaging solution...

When I take a beachball and force it underwater it is almost impossible due to the upward force of the buoyancy. Is there a way to determine what that upward force is based on volume of the object, or viscosity of the liquid (including air and balloons). How does one figure that? Since the...

I am looking for guidance on how to successfully measure vacuum using a device similar to a pirani gauge, my device however is a tungsten filament which is heated electrically to about 90*C, and it's current draw is a measure of vacuum.The problem I am having is how to relate specifically the...

I am looking for sources which describe how to measure the contact angle between immiscible liquids in a tube. The literature seems to be extremely lacking so if anyone has any knowledge I would appreciate the help.

I was just curious... what is the practical reason behind having two separate units for measuring volume? For instance, we can use cubic centimeters and mL interchangeably in practical medicine, i.e. injections. But we tend to use cubic (centi)meters for solids, and liters for liquids/gasses...

Consider a sample consisting of {y1,y2,...,yk} realisations of a random variable Y, and let S(k) denote the variance of the sample as a function of its size; that is S(k)=1/k( ∑ki=1(yi−y¯)2) for y¯=1/k( ∑ki=1 yi) I do not know the distribution of Y, but I do know that S(k) tends to zero as k...

If I'm correct, a series of with respect to some property entangled particles exhibits a correlation between several measurements of that property by means of two measuring devices. My question is: is it possible that between measurements the physical constitutions of the measuring devices...

Let's say I have a simple small DC motor. If I measure the current by putting two multimeter leads on the positive will it be a different value then if I were to measure it on the negative? My guess is that the current measured on the negative lead will be lower because the energy used in...

Hello, I am currently working with magnetic nanoparticles that aggregate and can be measured on the micro scale. Part of the project involves measuring their velocity as it move through vrious liquids. My current set up is simply timing their distance traveled. Does anyone know of a more precise...

Is it possible to build an apparatus that could do the following (at least ideally in principle)? If so, what would it be like? A fairly localized light wave packet (with a corresponding spread in momentum) reaches the origin of our coordinate system from any direction in the XY plane (taking 2...