Sources Definition and 538 Threads

A tertiary source is an index or textual consolidation of primary and secondary sources. Some tertiary sources can be used as an aid to find other sources. The exact definition of tertiary varies by academic field.
Academic research standards generally do not accept tertiary sources as citations.

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  1. L

    Is it possible for two planets to merge and still sustain life?

    Hi people! Strange request but not having much luck in anything specific to what I'm doing, either that or I'm not sure what i should be searching for... I'm making a fantasy world for a book and wanting to create a single planet that is still distinguishable as having been 2 separate...
  2. S

    How do dependent sources change the analysis of a circuit?

    Homework Statement Homework Equations v = IR The Attempt at a Solution Okay, so up until this point, I was doing okay... but now I'm stuck. I do not understand how I'm supposed to work with this because until now I have not had a dependent source. Am I supposed to start by doing a KCL on...
  3. E

    Two Parallel Voltage sources and KVL

    Hi, I understand that you cannot apply KVL to voltage sources connected in parallel, unless both voltage sources are the same, as this violates KVL. However, I want to know why? Just a simple 2-3 line explanation will suffice. Regards
  4. Q

    Kirchhoff's voltage law with current sources

    When you are using Kirchhoff's voltage law and you come across a current source, what should the sign of the voltage be?
  5. N

    Calculating Power Supplied by CS and VS Sources

    Homework Statement |----------| |+ |+ CS VS |- |- |----------| The current source is pointed downwards and is 2A while the VS is 12V They are asking for the power supplied by each source. Homework Equations V=ir KCL KVL P=Vi,i^2R,V^2/RThe Attempt at a Solution...
  6. jegues

    Loading effect on Voltage Sources

    Homework Statement See figure. Homework Equations N/A. The Attempt at a Solution Okay first off I have a little confusion about the diagram in figure 3. Is Vnl simply the voltage across the oscilloscope in this figure? Is the circuit I've drawn in pink the same as figure 3...
  7. N

    Scalar field energy for two delta function sources

    I'm trying to evaluate the energy shift in a scalar field described by the Klein-Gordon equation caused by adding two time-independent point sources. In Zee's Quantum Field Theory in a Nutshell, he shows the derivation for a (3+1)-dimensional universe, and I'm trying to do the same for an...
  8. C

    Surge Protector - strange reaction to light sources?

    Surge Protector -- strange reaction to light sources? We have 2 power strips in our home in which the indicator lights both react to a light source in the following manner: during the day (in the presence of sunlight) the indicator lights shine red with a small flicker every now and then. In...
  9. P

    Wave Generation from Point Sources: Interference Patterns and Radio Aerials

    Hi Everybody! I have been wondering about wave generation from point sources, and interference. I have noticed that if several point sources are sited in a line much more than one wavelength long, a very directional interference pattern develops. The closer the sources and the longer the line...
  10. A

    Confused with Nodal Analysis and Voltage Sources! HELP!

    The question might be simple for you guys but the problem is that it is not for ME ! I have a circuit and I have to determine the node voltages by Nodal Analysis method. And the one which I learned was in cases when we had a current source, I could simply write the equations using KCL...
  11. L

    Optimizing Pump Mixing in a Dual Pump System for Titrations

    So, this seemed most appropriate for this forum, as it's essentially a question about pumps, pressures, and fluid mechanics. The set up I have that this question pertains to; There are two pumps that have lines running to a T-joint with a small chamber to allow for mixing before exiting...
  12. A

    Dual Light Sources in Dual-Slit Experiment?

    I'm curious if the dual-slit experiment has been performed using multiple light sources. For example, if two photon emitters were used at various distances apart from each other, I wonder if that would affect the interference patterns. I'm wondering about this because the distance between...
  13. G

    Diffraction and Huygens sources

    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...
  14. E

    Help with thevenin - dependent sources

    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...
  15. J

    Help with PSpice/OrCAD Voltage Dependent Sources

    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...
  16. J

    Two sound sources and minimum sound points

    Two sound sources 4 m apart have the same frequency of 880 Hz. The sources emit energy in the form of spherical waves. An observer initially hears a minimum sound, since the sound sources are out of phase, at a distance of 15 m along the perpendicular bisectorof the line joining the two...
  17. N

    Proper way to cite your sources?

    ...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?
  18. S

    Sources of noise in geostationary satellite attitude determination simulation

    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...
  19. S

    How do supersonic sources create sonic booms?

    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...
  20. S

    Sources for Centrifugal Compressor design

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

    Photons from separated sources can be entangled - after they were detected

    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...
  22. W

    Interference of Waves from Two Sources and Beats

    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...
  23. G

    Hello Can someone tell me what sources in the Universe produce

    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...
  24. S

    Do Current Sources Really Exist?

    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
  25. S

    Can Public Finance Be Reformed to Create Debt-Free Public Assets?

    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...
  26. T

    Conservation of Momentum- Help with sources of erorrs?

    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...
  27. T

    Help- Physics Momentum Lab Sources of Error

    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...
  28. P

    How Do Radio Waves Interfere When Reflected from a Wall?

    [b]1. Problem #3 A radio transmitter is placed in the origin of a Cartesian coordinate system and emits a signal at angular frequency ωo. The signal from the transmitter travels freely along the positive x direction until it reaches a wall, at a distance L from the origin. The wall reflects...
  29. D

    Radiance Estimate of He-Ne Laser & Tungsten Lamp

    Homework Statement Estimate the radiance (in W cm-2 sr-1) of the following sources: (1) A He-Ne Laser, with a beam area of 1mm2, output power of 1 mW and a beam divergence of 1mrad. (2) a 100 Watt tungsten lamp at a distance 1 m from the lamp. Homework Equations Well, what I have is that the...
  30. R

    Exploring Outdoor Path Lights and Their Power Sources

    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...
  31. I

    Density Relationships - Cant find any good sources.

    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...
  32. R

    How Does Light Intensity Vary with Distance from an Incoherent Extended Source?

    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...
  33. I

    Switching 2 AC sources to a single load

    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...
  34. O

    Engineering Nodal analysis algorithm applied to a circuit without voltage sources

    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...
  35. D

    Kirchhoff's Law and current Sources?

    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)...
  36. Redbelly98

    LTSpice question, dependent sources.

    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...
  37. B

    Voltage and current sources; circuit

    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.
  38. A

    Quick query regarding voltage sources

    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...
  39. P

    What is the Contribution of Segments AB and CD to the Magnetic Field at Point O?

    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...
  40. T

    Inflaton and the boltzmann equation's density/velocity sources

    Hi, I'm looking for a resource which explains how the inflaton (and metric) perturbations are related to the CMB; in particular a lot of common sources (Dodelson in particular and some reviews I found on arxiv) simply state that the photon-baryon fluid has a 'monopole' (density perturbation)...
  41. P

    QFT: Exploring Connected Diagrams & Single Sources

    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...
  42. L

    Which of these radiation sources gives a higher dose rate?

    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...
  43. A

    Connect two AC sources in parallel unless they have the same voltage

    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...
  44. Lisa!

    Noises from MRI Imaging: Sources Explained

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

    Selling Processed Data from NASA and Journal Sources

    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...
  46. E

    Two AC power sources - connection?

    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...
  47. C

    Max distance of resolution from 2 point sources of light

    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...
  48. M

    Historical interpretations - where can I find sources?

    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...
  49. S

    Is the Rise in CO2 Really Not from Fossil Fuels? A Critique of the Quirk Paper

    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...
  50. C

    Power in voltage/current sources, passive sign convention

    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...
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