Sources Definition and 538 Threads

Is anyone here involved in the search for new energy sources?

Any recommended books, published pieces, online articles, youtube videos to help understand (or at least introduce me) Quantum Physics? Hell, a college thesis would suffice.

Last year I tried Single Variable Calculus (very good course) and look some videos of Multivariable Calculus on MITOCW and I cover almost all the material. So, when I took that course I realized I want to learn about mathematics. I want to be a PhD physicist (and I know that it cover a lot of...

I know none of the source can perfectly be monochromatic. All that we can talk about is the degree of coherence. What I wanted to know is that suppose magically some how I get two independent perfect point sources of monochromatic light, then will then two independent sources be act as...

Let's say I start at the high voltage part of the Emf source on the right and go counter-clockwise; the first thing I hit is the 10 Ohm resistor, and the current would not split up the junction because the wire is open-ended, correct? So the next thing I would hit is the 8 Ohm resistor, then the...

Homework Statement Derive the differential equation that relates the voltage (V) to the current (I) entering the circuit. Homework Equations Let: ic = C dV/dt = current traveling through the capacitor (C) ik = (V+Ek) / Rk = current traveling through the potassium (K) channel iNa = (V-ENa) /...

I know calculus, multivariable calculus and classical mechanics. So, I'm thinking about doing a project about rockets, so I'm looking for sources to learn about Rocket Science. Do you know good sources, like courses, books... for a 15 years old?

I'm doing a lab where we use three strings connected to a ring, with each string attached to separate spring scales. What would be sources of error in this? And how does friction affect my results?

I want a better visual model of what Newton's gravitational force formula represents: (G⋅m1⋅m2)/d2 But there are two contradictory things that I'm having trouble reconciling: Multiplying the two masses shows a relationship between the two point sources, but using the area of the sphere to...

Hello, I recently went through Griffiths' Quantum Mechanics text and there is a chapter called the Adiabatic Theorem that includes Berry phase and the Aharonov-Bohm effect. As I found them very interesting, I would appreciate if anyone could provide me with some good sources(books, internet...

Hello I am a rather new student in the field of quantum physics and I am very interested in quantum locking. I was wondering if there was anyone that had any good sources for understanding this subject better? Books websites, personal experience, interviews, anything at all would be absolutely...

I feel like it's hard to find good political news and commentary that's unbiased and reputable (Fox News ought to be shut down). What are the most popular, reputable, and unbiased sources that you guys know of (if any exist!)?

Hi, I have a question that might involve politics so I post it here. In the near future when fusion energy become successful, cheap, low-cost, small size, high above break-even point, etc. are there any role left for other alternative energy such as solar, wind, etc? Do we need those...

I have read, and seen it claimed in another old thread, that Galileo was the first to measure the free fall acceleration near Earth's surface. I have not found any source that explains how he did so or what his result was. I've skimmed through most of his Discorsi and have not seen it there...

My first ever post here, so hello world! So I've attached an image of a conventional 4x4 system with one RIC engine and LSDs for all wheels so that all four wheels can be driven, or just one depending on conditions. the front/rear LSD may in fact be locked, but that isn't particularly...

Assume that we are given a big black box with two windows. Each window emits a laser beam. All our best measurement techniques show that the two beams have the same wavelength and have near-perfect mutual coherence (or as good as the self coherence of each output beam). Is it possible to tell...

Hi My prob theory is rusty and I am a little embarrassed I can't figure this one out - but: If we have two sources A and B that are producing an output at different frequencies - say A produces outputs every 100ms and B produces an output every 250ms .. Obviously even if they are perfectly...

I am standing in the middle of a train. There are two lightsources attached to the train. One in the front, and one in the back. Both aimed at me, both with the same distance from my position in the train. No matter how fast the train is moving, i will always stay equally distanced to them. The...

Homework Statement This isn't a homework problem per say but I am struggling with what we are doing in class at the moment which is to do with circuits with two sources of Emf. More specifically, how one source can be used to re-charge a battery. I have looked at the following website which i...

Homework Statement A family ice show is held at an enclosed arena. The skaters perform to music with level 80.0 dB. This is too loud for your baby, who yells at 75.0 dB. (a) What total sound intensity engulfs you? Homework Equations I ∝ A2 The Attempt at a Solution Why did the answer sum...

Hi guys, I'm working on a school project and I don't know a lot about electricity, so here is my question. Let's say that I have two small 6V DC generators, and I need an output of 12V (I can not use a 12V DC generator because space is limited, the two 6V fit perfectly) is there a way to...

The lab called on us to use a vacuum tube to determine an electron's charge to mass ratio. Here is a link to the lab: http://www.clemson.edu/ces/phoenix/labs/cupol/eoverm/index.html. What are some sources of error in this lab? I already know that human error and error in measurement can skew...

Hi All, I have a basic question. I am still new to nuclear engineering so this maybe a stupid question, but what is the typical energy efficiency of a neutron source? (I.E. power of neutrons emitted/power input for neutron generation) I recognize that the efficiency can depend on the neutron...

Suppose we have a charge, ##q## and a magnetic dipole moment, ##\vec m##. They don't move, nothing changes with time, in short, a static situation. Now, we have at least some regions of space where both the electric field, ##\vec E## and the magnetic field, ##\vec B## are non-zero. That means...

Homework Statement Homework Equations KCL and KVL The Attempt at a Solution The sum of the currents at the top node equals the current out through the middle (Call ##I_1## the current from the left and ##I_2## the right) ##I_3 = I_1+I_2## And the sum of the voltages around the loops...

I am typing up a lab report for an introductory chemistry course. Basically we determined the entropy and enthalpy for the dissolution of potassium nitrate in water. The exp. values I found are close to each other but I'm supposed to compare to literature sources and I'm finding frustratingly...

Hey guys, I found summer work with a post-doc in my University. I will be working with him on a side project that he's had an interest in for some time, but could only start it this coming summer because of lack of time. However, because he's only a post-doc (and I only got the position by...

Did they read the recent physics papers about the atoms? Overall what sources of information did the old Manhatten Project Scientist like Edward Teller and Robert Oppenheimer use? I bet they must have really enjoyed what they did to be so good at it.

[Mentor note: thread title reworded] R = 1.00 k and = 250 V in Figure P28.25, determine the direction and magnitude of the current in the horizontal wire between a and e. http://www.webassign.net/pse/p28-23.gif I found a solution online...

Homework Statement I need to find the voltages (if any) and currents of these circuit, but particularly Io I do know that I have to use KCL bot I don't know how, can somebody help me with a node or somethinghttps://www.physicsforums.com/attachments/c2-jpg.80412/ I do not have any other info...

Hello all! I'm hoping you will be able to direct me to sources of raw income1 / employment data. Hopefully this thread can be a help to others who have similar needs in the future, as well. (I did a quick search for a similar thread and didn't find anything - please correct me if I'm wrong.)...

Here is the circuit. I have to find the voltage across each resistor and the current i1 and i2. My attempts are the following: By KCL, i2 + i1 = 0.1 A By KVL, 3 - 5 - 100i1 + 1100i2 = 0 ∴ i1 = 0.09 A, i2 = 0.01A ∴ Voltage across 100Ω resistor = 0.09 × 100 = 9 V, voltage across 1100Ω resistor...

Is it possible guys to add it that way? Well what i did is that i add the current sources even tho they are not parallel because of the voltage source... But it can be considered a node the upper part if you use super node... The one that is encircle is done by my prof... saying I'm wrong... but...

Can i add these current sources even though they are not parallel since the voltage source can be a node by applying super node? i get the same answer by using nodal analysis... but i want to know if its applicable. replications of attachment removed by a mentor

Homework Statement Jane waits on a railroad platform while two trains approach from the same direction at equal speeds of 11 m/s. Both trains are blowing their whistles (which have the same frequency), and one train is some distance behind the other. After the first train passes Jane but...

i go to school, and it's quite far away (3 hours per day, return), so, i'd like to use this time wisely and learn QM, but unfortunately, i can't read books on transportation, i get dizzy... when i read things for prolong period of time.. i've only learned about the special relativity, and am...

I have limited physics knowledge, but I have always been interested in the physics and I am an industrial radiation safety officer with an engineering background.Have there been any experiments in respect to measuring half life with large variance in gravitational fields? Although half life may...

I am cc student pursuing a degree in mathematics. I will have at least a 3.5 gpa when I am ready to transfer. My school counselors are not the most caring and informative individuals. I tried a google search, but it seems I do not know how to do research by using a search engine or I do not know...

in my AH physics investigation - measuring acceleration due to gravity, I used the bifilar suspension pendulum btw a light gate was used for the errors/problems section so far I have problems in making the rod level and keeping the two strings parallel, also all the random, calibration and...

completing my advanced higher physics investigation - measuring acceleration due to gravity for the oscillating mass on a spring experiment so far I have included friction between the nail & oscillating rod as a possible source of error can anyone think of anything else? thank you very much...

I see that the formula for hawking radiation is related the the formula for unruh radiation. The accelleration experienced by a body yields an unruh temperature equivalent to a black holes hawking temperature with an equivalent value of g. The unruh effect happens at all accelerations, therefore...

Hi all To observe interference of light waves in Young's Double Slit Experiment one needs to have coherent sources.Some,doubts are coming in my mind regarding coherent sources. Q1. Will it make sense to talk about a single source as coherent source(not sources) Also two(or more) sources are...

I can get a measurement of my distance between points (x1,y1,z1 and x2,y2,z2) by analysing position data from a GPS/barometer system, which has a standard deviation of about 2m for x y z positions. I can also analyse data from a system that provides velocity with a standard deviation of about...

Homework Statement [/B] we used a laser pointer as a light source Homework Equations I'm having trouble looking for an error in the experiment. The Attempt at a Solution

When two batteries/power supplies are connected in series their current must be equal while the voltage is increased. Why is that so? Why wouldn't current increase equally as voltage increasing when connected in series? Just wanted to understand the theory behind this.

Homework Statement If we have two AC sinusoidal voltage sources in series with +ive poles in the same direction (A... +u1- ... +u2-...B), Find voltage phasor \underline{U}_{AB}=? (underlined means phasor, complex) - magnitude and phase angle, and find momentary value of voltage u_{ab} at moment...

My first question from his first volume. On page 254, he writes down the action expression: (3-10.1)W=\int (dx)[K\phi+K^{\mu}\phi_{\mu}+\mathcal{L}] Where the lagrangian is: \mathcal{L}=-\phi^{\mu}\partial_{\mu} \phi +1/2 \phi^{\mu}\phi_{\mu} -1/2 m^2 \phi^2 The consideration of...

Homework Statement For a fixed given electrical power to two monopole sources, producing the same frequency. Which mode, either in-phase or out of phase, will radiate the most sound power into the far-field? Homework Equations Is the radiated sound power dependant of the given electrical...

Hello all! I'm confused about an explanation that my textbook gives, and I'm wondering if someone can help me understand it. The passage is as follows: A circuit consists of a 12 V battery with negligible internal resistance, in parallel with a charging unit with an emf of 15 V and internal...

I'm building a spaceship and making a movie where a long spaceship is encased in laser shielding that doubles as laser propulsion. Plutonium is 1 power source ideally between the sun and target star. The movie is titled The Finish Line. Clear pipes around the ship are filled with water and...