Sources Definition and 517 Threads

Hello, I'm pondering on why bending occurs most when the width of the aperture is close to the wavelength of the propagating wave. According to Huygen's principle, should'nt there be point sources around the edges of an aperture regardless of the width and thus the bending propagate to...

Homework Statement It is not so important for my question Homework Equations So first of all, sorry to just barge in and post this question, but I am not sure how to solve it. I have attached images of the circuits. The task is to find the equivalent thevenin or norton generator. My problem...

1. Right now I am trying to recreate a problem from the book with pspice however, the math I have performed on the problem is not the same as what pspice is telling me. 2. Also how do I represent a voltage that has exponential decay with time (such as 5e^(-t)) 3.here is the problem(finding Vy...

...in a math research paper that is. I really have no idea. I'm assuming it's different than MLA. Is there a website or something out there that has the guidelines or is it different for each journal?

I am doing satellite attitude determination simulation using sun Earth sensors and Gyro modelling .I am using extended kalman filtering for attitude determination. the sequence of operations I am doing are % Simulation data % Spacecraft data % Gyro data % Sensor data. % Control system...

Why do supersonic waves (when the source is faster than the wave) create sonic booms? I understand that when a source breaks the sound barrier and travels at the speed of its waves, the waves just build up at the front of the source and create a condensed sound of multiply sound waves added...

I would like sources for centrifugal compressor design. Anything, such as books, e-books, journals, websites, etc. will do.

Yes, I know the thread name sounds like something you might see on the cover of Discover (or sadly, Scientific American these days). Hey, I could have called it: Proof that the future changes the past! Because that is precisely what happens. The subject relates to entanglement swapping. In...

Homework Statement Two loudspeakers emit 300 Hz notes. One speaker sits on the ground. The other speaker is in the back of a pickup truck. You hear eight beats per second as the truck drives away from you. What is the truck's speed? (Assume that the speed of sound is 343 m/s.) Homework...

Hello.. Can someone tell me what sources in the Universe produce anti-matter? Do black-holes, stars? stellar explosions? I can assume if these things are large in number...there should be a lot of anti-matter floating around in the Universe. I know a lot of it gets destroyed in the...

hi all I want to know that,do 'current sources '(which supply current) really exist in the world or it is only theoretical concept? if it exists than please give some example. thanks

I've been thinking America needs to reform our system of public finance. The current system uses debt-money to finance public goods through the bond markets and investment banks. Thus public goods are perpetually encumbered by debt rather than created debt-free. Obviously it is possible to...

Hey everyone. In class, we conducted a lab to verify the law of conservation of momentum. On a frictionless surface (glass surface), we had to collide two masses and record the time, and then make calculations for the velocity... and using that, calculate the initial and final momentums and...

Hi Everyone! I'm a grade 12 physics student and we conducted a momentum lab. On a frictionless surface, we conducted a simple 2D collision and using the data gathered from that, we had to calculated the momemtums and indicate what type of collision had taken place... that was all fine and done...

First of all, I'll say that I do not have much experience in electronics, but I am relatively competent. So, to the point; have any of you seen those outdoor path lights that have a solar cell on the top of them? They charge during the day and light up with LEDs at night. Does anybody know...

Im working on the conclusion for my lab report, and rather than plagiarize the work like most I know, I am trying to write it myself. I've spent probably between 30-40 hours on it so far, so don't think I am trying to cheat or get ahead here. But I need to describe relationships of density to...

I'm currently trying to look into the optics of extended sources. Google doesn't seem too helpful. Anyway, I have just been thinking about it and thought that surely one of the easiest problems would be the intensity at a screen at a particular distance from an incoherent, spatial extended...

Greetings, I would like to build a circuit that would switch 2 separate AC power sources to a single load. Here's what the circuit should do: Circuit has single AC output to a system which utilizes AC current Circuit has both a 120 VAC and 12 VDC input. 12VDC circuit is connected to an...

Homework Statement I am having some trouble with the nodal analysis algorithm explained in this web page http://www.swarthmore.edu/NatSci/echeeve1/Ref/mna/MNA3.html My electrical circuits knowledge is very basic, and I need to get the equivalent resistance of a circuit for a non related...

When you are using Kirchhoff's voltage law and you come across a current source, what are you supposed to include that as? Pretending that it is an ideal current source, there will be no resistance and thus no voltage drop. So, do you just ignore it in the voltage equation? (Ex: V1+V2+V3=0)...

I use LTSpice, and vaguely remember there was a way to make a voltage (or current) source depend on either another source in the circuit, or to follow some function of time. I think it's either a source parameter, or a command line placed in the schematic. Does anybody know how to do this...

Homework Statement For the circuit, if V2=1000i2 and i2 = 5mA, determine Vs Homework Equations The Attempt at a Solution I'm really stuck here for some reason and have no idea where to start. Any pointers? KVL and KCL is in the next chapter, so I think I should be solving without those.

If you had a DC voltage source that supplied a voltage V volts and you connected a resistor of R1 ohms to the + and - terminals of this source then shorted the resistor with a wire of little but measurable resistance - R2 ohms would the following happen: *would the wire draw high current...

Homework Statement http://s619.photobucket.com/albums/tt272/babyazureyoshi/?action=view&current=014.jpg Homework Equations 1) B_x = (µ_0 * I) / 2R at x = 0 The Attempt at a Solution I know that segments BC and DA do not contribute to the magnetic field at O so all I need to know is...

hi all, i have a question regarding page 81 in Srednicki's QFT book. He states there that the sum over all connected diagrams with a single source is zero. Then he says that if you replace this single source by an arbitrary subdiagram the sum will still be zero. Can somebody explain why this...

Both are point sources. Source A emits 500 KeV gamma-rays, while source B emits betas, with maximum energy of 500 KeV. Assume that the sources have equal activity, the same range, and are close enough for absorption of betas in air not to be a factor. Which gives the higher external dose rate...

basically, you can't connect two AC sources in parallel unless they have the same voltage, frequency and phase. OK, know I undestarnd what u guys meant in the above sentence. Now, talking about the PHASE, can you give me any advise, links, recommendation, book (anything), on how to get the...

What is the source of noises we hear during MRI imaging? Thanks!

If I were to take published data from public NASA reports and printed Journal articles and sell the data (after doing some processing to it), would that be grounds for a lawsuit against me? I'm wouldn't be selling the article itself, but taking important data from articles over a span of 40...

two AC power sources -- connection? i am working on a control system for a compressed air energy storage system for a wind turbine (generates ac). the goal is to shave peak power consumption, so at night the compressor will charge (either by the wind or by the grid), and during peak hours, it...

Homework Statement Two point sources of light are separated by 4.91 cm. As viewed through a 12.1 μm diameter pinhole, what is the maximum distance from which they can be resolved if red light (λ = 690 nm) is used? Homework Equations sinθ = 1.22*(λ/D) y= L*tan θ The Attempt at a...

Hi, I have to write an essay for a class and I'm a little overwhelmed. My topic of choice is how different cultures and societies interpret historical events. (For example, how do the Japanese interpret WWII in comparison to how we interpret WWII?) It's somewhat of a research paper, but I have...

http://icecap.us/images/uploads/TomQuirkSourcesandSinksofCO2_FINAL.pdf" is a paper published in Energy and Environment that claims the rise in CO2 is not from the combustion of fossil fuels. I am in the process of reading it now and thought I would share it here. The first thing that...

Homework Statement Determine which of the five sources in Fig. (attached) are being charged (absorbing positive power), and show that the algebraic sum of the five absorbed power values is zero. I've labelled how I'm referring to the sources in red...

Homework Statement Homework Equations My answer: I_C=(\frac{1}{6}-\frac{1}{2j})(cos(2t)+\sqrt{2}cos(2t-0.25\pi)) THIS IS WRONG.The Attempt at a Solution The way I went about doing this was: 1. Ignored V2 and worked out the total impedance in the circuit for V1. 2. Calculated the voltage...

Homework Statement Basically, the problem involves a linear system dx/dt = ax + by and dy/dt = -x - y, with a and b being parameters that can take on any real value. Basically, you go through this system for several values of a and b (I did -12 to 12) to find the state at various points...

Hello there, it's my first semester in Physics I, so I'm not exactly sure which is which. If someone would clarify what these are, that would be wonderful. They're for our lab report. - Principal Results - Sources of Uncertainty (in order of importance) This is our first lab...

Hi! Good day! I was studying Circuit Theorems when I stumbled upon this circuit that has a dependent current source asking for a Thevenin equivalent. Up until now, I was only familiar with solving circuits with independent sources so this has me having a hard time. I tried using...

The pole still has extremely strong gravity, how can a sphere suddenly concentrate the radiation at the pole to be emitted there ? As this is the only exit, should there not be a strong deformation ? How does the radiation make it to the pole, or, is the radiation we are getting only from...

I'm trying to find a DC motor in the 3-3.5kW 12-24V range (Preferably 24V) for a project that will utilize the motor at maximum power for occasional short bursts of maybe 2-3 seconds in duration at most. The motor needs to be fairly small, lightweight, and CHEAP ($100 or less). Starter motors...

I'm an IT person - non-scientist - but this problem has challenged me ever since high school physics: If two permanent magnets - pole to like pole - repel each other, the magnet suspended possesses potential energy. If a material can be found (that is non-magnetic and without any power...

Can two independent sources of light be coherent?

Can someone solve this circuit Find v and i in the circuit. I know that we have to make somethng with supernode, but where the supernode is here? How to develop this problem? Please help me :) Btw it is nice forum, today i have found that. I hope I will be able to help you in other...

I believe in something very strongly, and that's that "right and wrong" are human fabrications, and are not tangible constituents to the nature of reality. When a young child is sexually assaulted and killed, consider what no one else ever does; what is the ultimate consequence for the universe...

Hey! I'm trying to create something with some power cells, and I've run into the issue of inconsistent power supply. I'd like to supplement power from a solar cell with a battery, but I'm not exactly sure how to keep the input to something at a set value. Basically, when the solar cell...

In the following circuit what does the current source mean? Am I supposed to use 3A to determine how much voltage is running across the 10 ohm resistor? If not, how do i determine how much voltage is running across that resistor? i need to know so i can determine the final equation of my set of...

I want to be involved in the research for searching for new forms of energy, to decrease our energy dependence. I am a starting senior in high school, and want to know what I should declare my major as. (As of now, I'm just going to go in as Physics most likely)

Homework Statement Find the potential differences across the 5 ohm, 4 ohm, 3 ohm, and 2 ohm resistors. Homework Equations 5I_1-4I_2+3-12=0 Left Loop 3-18+5I_3-4I_2=0 Right Loop 12-18+5I_3-5I_1=0 Whole loop The Attempt at a Solution I simplified the first diagram...

Sorry if this is stupid question, but I am just curious. And sorry if I posted in wrong forum but it seemed to um... Fit the most. And sorry if my English isn't perfect :). Ok now, the title might be a bit confusing. What I am looking for are the most efficient energy sources, which are...

Homework Statement Having a real tough time with this problem was wondering if anybody could help Two identical loudspeakers 2 m apart are emitting 1800hz sound waves into a room where the speed of sound is 340m/s. Is the point 4m directly in front of one of the speakers, perpendicular to...