Uncertainty Definition and 1000 Threads

Homework Statement This is about experimental physics. I have a value of resistance R=9000 \pm 1000. Then I had to do the following calculation: \frac{40000}{9000}=4.44 \ \Omega So, I'm not quite sure how to calculate the final uncertainty from my uncertainty \sigma = \pm 1 \ k\Omega...

So to determine the position of an object you can scatter light off of it. Fine. But then my textbook says you can't know the exact position of the object because of diffraction effects. We've covered the diffraction of light through narrow slits but I don't know why if you were scattering light...

I have been trying to figure out other pairs of variables in Heisenberg's uncertainty relationship apart from the well known position-momentum and time-energy pairs. I am particularly interested in electric fireld strength and magnetic field strenght. The reason for my interest is that if I...

Homework Statement Heisenberg's uncertainty principle states that you cannot simultaneously know the position and momentum of an object. In this video link, a laser is aimed through a slot and projected onto a wall. As the slot gets narrower, the projection also gets narrower. Eventually...

Hey I'm hoping for some help in understanding the relationship between ##\delta x \delta p \geq h## and ##\delta k \delta x \approx 1##. I know the second describes the relationship between span of a wave packet and the frequencies used in a series representation of a Gaussian function. I...

Homework Statement A neutron in an atomic nucleus is bound to other neutrons and protons in the nucleus by the strong nuclear force when it comes within about 1 fm of another particle . What is the approximate kinetic energy in MeV of a neutron that is localised to within such a region? Take...

I'm trying to write a lab report. I've taken some measurements several times and have calculated the results and the systematic uncertainty for each set of measurements. i.e. I have x_{i} s, which are the results, and I have \Delta x_{i} s, which are the systematic uncertainties, calculated...

This is my first post here, and I just want to add the following disclaimers: I'm not in university, and I have never taken a physics class proper in my life. xD I want to say I understand quantum mechanics in principle, as while I think I understand many of the concepts I do not know it...

Is this explanation of uncertainty principle from wikipedia correct? Is this "compressing" the Fourier series/integral? Because the function is not periodic, and with infinite frequencies some of then would put make the speed greater than c "According to the de Broglie hypothesis, every...

Homework Statement I don't know how to do 13.10 and 13.11 http://a367.yahoofs.com/hkblog/LR5wVsiTBB9XH4KDYpBfXDI-_9/blog/20110511014559607.jpg?ib_____DMAbgW2U6 The Attempt at a Solution I just can't get the answer. Can you show me the details of the proof and the steps to the...

Hi, (this is my first post! : D ) I'm a freshman in college. I came in wanting to major in physics and English. I soon tossed english aside and immersed myself in the sciences(during like the first month). I took Physics 1(general overview course touched upon all topics of physics from...

It seems the book makes a mistake. Uncertainty principle states: (Uncertainty of p) times (uncertainty of x)>=(a constant) But in the following picture, the writer calculates the exact value of momentum and find uncertainty of x. Is it wrong? I am using Understanding Physics written by...

Some people suggest that free will is proven by the heisenburg uncertainty principle, which states that you can not predict the outcome of a quantum event. Does this mean that humans can some how consciously tell every electron in their body how to act in order for their desires to be fulfilled...

I have some data (4 runs each of about 10 trials) which is binomial with n_hits/N_trials n/N = 0/11, 0/9, 0/10, 0/10 So, I estimate the probability p = n/N = 0 But how can I calculate an uncertainty on this value? I thought to try total N_tot=40 and n_tot=1, so p_tot=1/40 = 0.025 (i.e...

Warning: My understanding of physics is minimal let alone Quantum Mechanics so please excuse (but feel free to correct) my misunderstandings. My understanding of the Uncertainty Principle is that because photons have to hit a particle so that we can view it, we can never be certain of...

Homework Statement The relationship between resistance with temperature is expressed by the equation of R= R0[1+ α(T-T0)], where Ro is the resistance at the reference temp. T0 and α for the resistor material has been determined to be 0.0048 ± 0.1% oC. In the range 0 to 100* C, in which we...

Imagine humans had a size on the order of magnitude close to the size of a large planet. An electron, then, proportionality-wise, would roughly be the size of an apple. To us large-scale humans, the apple might seem quantum mechanical and unpredictable because it seems exceedingly tiny. But we...

Homework Statement show that |\DeltaE/E| = |\Delta\lambda/\lambda|<<1 Homework Equations \DeltaE>hbar/2pi\Deltat \lambda=hc/E The Attempt at a Solution dunno where to start.

I think I undetstand the role of the uncertainty principle in explaining the existence of interference patterns in the double slit expt with electrons i.e. the slits reduce the uncertainty in position and consuequently there is a greater uncertainty in momentum which results in interference...

1. Homework Statement [/b] 1)for an object of size 0.5 Angstrom, what is the longest-wavelength photon with which it can be observed? 2)for the object of problem 1, what is the smallest-energy electron which can be used to make the measurement? Homework Equations 1)\Deltap x \Delta x \geq...

Does the Uncertainty Principle apply to the calculation of particles in a past point in time? As in, can we know the momentum and position of a particle in the past?

Lets say I measure the z-component of a particles angular momentum, then I can't know for certain the x and y componets. So if I measure the Z componet to be 0, the x and y componets could be zero or not. So is it impossible to say that the particles total angular mometum is zero meaning...

Hydrogen Atom ---> Uncertainty Principle Hey guys, I'm having some trouble with this one. [PLAIN]http://img849.imageshack.us/img849/2039/physhw.jpg How do I get started?

Homework Statement In my lab we are doing Franck Hurtz experiment with heated mercury and electron beams. We already took data but i need a little help. I have the locations of the minimums A B C D and E, and each point has it's own uncertainty. a b c d and e. What i needed to find was the...

Homework Statement \phi(x) is in Schwartz space, and {\int|\phi(x)|^2dx=1. I need to show that (\int_{R^n}|x|^2|\phi(x)|^2dx)(\int_{R^n}|\xi|^2|\phi(\xi)|^2d\xi)\geq \dfrac{n^2}{16\pi^2}Homework Equations Heisenberg uncertainty in one dimension...

I'm trying to get my head round this. I don't see why our inability to measure the world around us means that at the quantum level things must be random. I understand that measuring momentum of a particle to a high degree of accuracy means losing accuracy in it known position. But I don't...

]How can H.U.P be used to explain the following : (i) The non-existence of the electron in the nucleus. (ii) The existence of protons, neutrons and alpha particle. (iii) The existence of finite zero point energy. (iV) The binding energy of an electron in an Hydrogen atom is of the order of 15...

How do time-energy uncertainty and special relativity's rules about observers seeing time different for each other interact? Heisenberg's uncertainty principal applies to time and energy: a system existing for a short duration of time has more uncertainty in its energy than one that exists...

hello I have some questions which I was struggeling with 1. Is percentage error the same as percentage uncertainty? Because percentage error is a measurement of accuracy and is percentage uncertainty also a measure of accuracy? 2. How do percentage uncertainty and percentage difference affect...

I was reading that a meter is the length of the path traveled by light in a vacuum in 1⁄299,792,458 of a second. So the speed of light is exactly 299,792,458 m/s. I am wondering what is the uncertainty in our most accurate measurement of the speed of light. For example say I had a machine...

Hello I was given following homework question. 2 gradients are given. gradient1 of the line is 0.503 gradient2 of the line intersecting the line above is 0.167. Find out the percentage uncertainty in the gradient. i thought you have to do (0.503-0.167)/0.503 is that right?Please help thanks...

Hi folks, I do read some of the interesting post on this forum particularly the discussions on the concept of uncertainty principle ie the more you know about the particle position the less you know about its momentum etc etc I am a complete novice and am trying to get the big picture here...

Homework Statement So I have this homework question and the answer that was given to me to check the answer that I have does not match with my answer. The question I have to complete is shown below: The answer given to me is D, 6.6eV Homework Equations \Deltat\DeltaE = h/2...

Homework Statement I'm looking at an electron-in-a-box with walls at x=0 and x=L; I want to calculate the uncertainty (delta p) in the measurement of its momentum: sqrt(<p^2>−<p>^2) for its nth excited state. Homework Equations The normalized wave function: psi_n(x)=sqrt(2/L)*sin(n*pi*x/L)...

We all know that our universe is headed towards a heat death with maximum entropy and useless energy. However, we know that a vacuum of space will always have energy greater than its local minimum (potential well) due to the uncertainty principle. There must always be random fluctuations...

Two observers A and B are in relative motion with a constant velocity[for example, along the x-x' direction].If A knows the the position of B accurately , the motion of B gets enormously uncertain[and vice verse] in his calculations/considerations.How is he going to derive the Lorentz...

We all know that you can supposedly never know the exact position and momentum of a particle, because the very act of measuring disturbs it. Now, why can't we have two particles that start out and evolve the same exact way but separately and, using one of them as a dummy, perturb it, extract...

Homework Statement Find the uncertainty for pi using (a) the formulas (b) calculusHomework Equations \pi = (4/D^{2})(hw - m/(PL)) Uncertainty formulas: for products and quotients: Z = XY \deltaZ/Z = \deltaX/X + \deltaY/Y for differences: Z = X - Y \deltaZ/Z = \deltaX/(|X - Y|) +...

Homework Statement I need to calculate the uncertainty for the velocity v_1=(cart length)/t_1. The cart length is constant. Homework Equations That is what I am not sure about. I need to use the rule "dividing by a constant" to find the uncertainty. Is that result q=B/x ,where B is...

To be honest, this is straight up advertising, but I think it'll be helpful to a lot of people. My friend has made an Uncertainty calculator app for the iPhone (android coming soon), and it has saved me tons of time. So I just want to support him. Here are the links and screen shots...

I'm in the process of doing a quantum physics lab and am having a bit of trouble with uncertainty. The specific things going on in the lab aren't relevant, I don't think, only the general procedure of my calculation. Also, I'm not certain where this question should be asked, so I decided to put...

Homework Statement A baseball player friend of yours wants to determine his pitching speed. You have him stand on a ledge and throw the ball horizontally so that his release point is 3.6 m above the ground. The ball lands 29.0 m away. a. What is his pitching speed? b. As you think about...

Does anyone know if there is an online english translation of Heisenberg's paper on uncertainty "über den anschaulichen Inhalt der quantentheoretischen Kinematik und Mechanik" Z. für Phys. 43, 1927. I haven't been able to find it so far, all I can find is one's in German...

Homework Statement Drivers that come to a stop leave different amount of gaps between their car and the car in front. It was found that the average gap was 1.45m, but as the values varied, the uncertainty was 25cm. It was also reported that the car is 5.1 ± 0.5m in average. What is the range...

I have a few questions regarding how/when to use which uncertainty principle formulas. I am not sure of the difference between them. I've checked my book and wiki and neither really helped. Here are the formulas in question. \Delta p \Delta x \approx \hbar \Delta p \Delta x \geq...

The Uncertainty Principle is an inequality relation but while its application, only the equality is considered. For example - to calculate the Mass/Energy of a particle produced during an interaction, the Life Time of the particle is used to divide the Constant (h/2). But in principle the...

Homework Statement Perform the calculation and report answer in proper scientific notation with absolute uncertainty 73.936(+ 0.19%) / [(0.00455+ 0.00096) + (0.011889(+0.73%))] Homework Equations Addition/Subtraction: Absolute uncertainty = square root(uncertainty[SIZE="1"]1 +...

I had a thought going in my head today about the uncertainty principle. Forgive me if it sounds too silly. Consider an electron in motion. Now, suppose that I'm measuring it's position with infinite accuracy. So, by the uncertainty principle, it's velocity is blurry. But what if I measure the...

I am trying to understand fully the concept of this principle. But this uncertainty stuff confuses me. Can someone give me the link, or some material so I can work mathematics behind this mechanism. Its not that principle it self is the problem, I have glimpse what's going on, but the...

Hey there, I have a problem to do, in which I need to determine the acceleration of an object and the uncertainty of the acceleration. The position vs. time equation is given by: s(t) = 0.205t2 + 0.3001t Therefore, after differentiation, I can state the the velocity vs. time equation...