Core Definition and 469 Threads

Homework Statement Assuming you know the core mass, and other data about the sun, such as temperatures and pressures. Find the density at the very center of a star. Homework Equations I think this may be involved. P(r) = p(r)/µmH kT(r) The Attempt at a Solution [/B] I don't know where to...

The Wikipedia page on gravitational time dilation (https://en.wikipedia.org/wiki/Gravitational_time_dilation) states: "Relative to Earth's age in billions of years, Earth's core is effectively 2.5 years younger than its surface." A clock subjected to less acceleration (gravitational or...

I formulated a statement about the repulsion between a permanent magnet and an air core coil (electromagnets without a ferromagnetic or ferrimagnetic core), and I believe this statement is true, but I would like to seek the opinion of others about it: "In a system where an electromagnet made...

Knowing the following information: Sun surface temperature of 5788 K, Sun's core is between 20-25% of radius. I tried to (perhaps naively) calculate the temperature to the edge of its core from the surface temperature, using an inverse square law. Depending on which value you use for the core...

How can we achieve "higher-resolution" 3D pin-by-pin core simulators "without spatial homogenization" for the nuclear reactor core (PWR/BWR) calculations? In regards to this question, is it okay to perform "pin-by-pin fine-mesh core calculation" and/or "cell-heterogeneous detailed transport...

Hello community, I can't find an explanation for something and I thought I'd come and ask you. I'm studying for a test I have tomorrow and I came across a problem of a three legged steel core with 400 turns on the center leg, the magnetization curve is given, the first part of the problem asks...

Hello and thank you for bothering to read this long mess . I have just finished high school and after researching the best universities for majoring physics I've decided to try getting admitted into MIT (I don't live in the states and my country [Israel] has mandatory military service so don't...

What makes the core of some chromospheric lines such as the transition at 8542 A of the infrared Ca II triplet appear in emission in the dark umbra of sunspots?

Homework Statement A long solenoid of 60 turns/cm carries a current of 0.15 A. It wraps a steel core with relative permeability ##\mu_r=5200##. Find the magnitude of the magnetization of the core. Homework Equations ##N=\lambda L## ##\chi = \mu_r-1## ##\mu = \mu_r\mu_0##...

Dear all, I have completed my MSc and PhD in Nuclear Engineering (Reactor Physics and Core Design) from a UK university. I am currently working at a National Lab in France. Can you please suggest/recommend me a site where I can find the most suitable jobs related to Nuclear...

When core collapse occurs, a ~10000km diameter core of the star collapses into neutron star or a black hole. Let's look at NS case here: the resulting neutron star is on the order of 20 km across. And this happens in a few seconds. The upper layers of the star cannot immediately fall onto the...

Is there an astrophysical relationship between the how large a star's core gets and how large the star itself gets? Is it a simple linear percentage, or something more complex? For example, red dwarfs can fuse their entire hydrogen allocation, so the whole star is the core. But the Sun has a...

How do I find out gauss from air core inductor 36mohm pumped with ~130amps 9ms long? http://www.parts-express.com/erse-25mh-14-awg-perfect-layer-inductor-crossover-coil--266-380 Greatly appriciated.

Hi. I have written a Fortran program to solve a pde, which has six dimensions. One of these dimensions is time, 3 are for space, and the other are related to velocities. The program works fine when I run it with ##38^3## points in space (one for each space dimension), and 80 other dimensions...

Say one has a solenoid with a given number of amp-turns; if the core is air, we know that the energy to charge a magnetic field to "B" Tesla is recovered when the magnetic field collapses. Now if that core is iron instead of air, we know the magnetic field is greater than the original "B" value...

Hi I am looking for places I can get iron core plates to make transformers. These are needed for prototypes I want to make. I have looked at microwave power supply’s. They would work but I would need to find a few with the same ones in them. I need just the cores and I will wire the copper up...

Hi, The figure given below was taken from "Nuclear Systems" by TODREAS and KAZIMI. it shows the effect of neutron reflector on the thermal neutron flux radial distribution. Is this correct? Because it does not show the extrapolated distance. It seems to me that the reflector, somehow...

So I need some advice of someone professional and experienced. I’m 16 just about to sit my GCSEs soon and I’ve got a plan of what I want to do in the future. I reckon for my age I know quite a lot about high end things in Physics to do with quantum physics, special relativity, string theory...

Why does an iron core increase magnetism? Apologies if this more advanced than high school. EDIT: Disregard, found article on magnetic reluctance.

I am taking an online course on Analytics Modeling from Georgia Tech. The introductory section included a link to a list of core Netiquette Rules, which I find pretty useful.

Homework Statement A solenoid of volume V, current I and n turns per unit length has an LIH core, relative permitivity is \mu_r. This core is then slid out so that a fraction f of the solenoid's length is filled with air/vacuum (and 1-f is filled with the core). Neglecting hysteresis, what...

For example how to calculate required cross-section area of the toroidal core for 100VA transformer.Is that any simple formula.

I want to make a stepper Motor. How to find the suitable core material. Can I use Annealed iron as core for stepper Motor? Will Eddy current loss will be more in it ? Is there any way to calculate diff core losses of diff material https://en.m.wikipedia.org/wiki/Magnetic_core Saw the following...

There aren't any eddy currents in the metallic core of the galvanometer , Although it moves in a magnetic field? If it's right , why?

What is the reason for enhancement in the intensity of emission due to the introduction of a shell in quantum dots? I do understand the blue shift in quantum dots but how does a shell enhance it?

Homework Statement A child sitting in a tree throws his apple core from where he is perched (4.0m high) with a velocity of 5.0 m/s [35 degrees above horizontal], and it hits the ground right next to his friend. A) How long is it before the apple core hits the ground? B) How far from the base...

For the Image given, i have to calculate reluctances of air gap and core which depends on respective mean path lengths. For the left hand core, the mean path length calculated in the solution manual is 1.11 meter . However what I don't understand is that why is the length of the air gap included...

Basic Question Alert ! (I need to brush up my basics and need your help) Problem Statement: I wish to make a current carring cable loop to generate a controlled magnetic field. http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/curloo.html As I understand, the magnetic field generated depends...

Designing a PWR core in MCNPX for burnup using 4 folds rotational symmetry to reduce computational time of the core, taking reflective boundary conditions on rotational symmetry planes. should the power be reduced to 1/4th of original power (3000 MWth) in burnup card or does the reflective...

As the star runs out of nuclear fuel, some of its mass flows into its core. Eventually, the core is so heavy that it cannot withstand its own gravitational force.The core collapses, which results in the giant explosion of a supernova. Source...

There seems to be a standard way of looking at the composition of planets, and am curious as to why one region is called the core and then something above that is the mantle, and then finally the crust. It seems that the core is metallic, but what exactly defines the mantle & crust. I was...

Hello there I'm working on this problem: Solve numerically for the eigenvalue and neutron flux distribution in a slab reactor consisting of two adjacent core regions each of thickness 50 cm, with a 25-cm-thick reflector on each side. The nuclear parameters of the two core regions are (D = 0.65...

Please excuse me if this is a very basic question, but I am just hoping someone can enlighten me on something. I am using the program FEMM to simulate a transformer. Unfortunately, I am unable to find data on the BH Curve of the material I’m using for the core, and I am worried that my...

Even if the outer core is convecting and conductive it is still charge neutral, so how can a Magnetic field be generated? Maxwells Equation say there needs to be net charge moving for a Magnetic field to be generated.

Common Core is evil. Everything is about funding and exams. One of my nephews came home with a math question that my brother could not answer. My brother is an IT Specialist for Western Union. He knows math but not Common Core math. Here is an example: Add 20 + 30. Old Fadhioned Method...

Is it possible to couple a 200μm core fiber into a 50μm core fiber by using a 4x magnifier/reducer?

I read here that the reason why gammas primarily interact with core electrons in an atom is that "As the difference between the photon energy and the energy required for the process increases, the cross section of the process decrease". Is that correct? If so is there any intuition for why that...

Hi, I have a question about steel, for instance, silicon steel used in magnetic cores. I was wondering about how Iron magnetises: can you align the grains/domains and heat treat it [or anything], so that it responds differently to flux one way then the other direction? For example, say you...

I am a student of electrical engineering. This task appears in our textbook. However, there were no solutions provided. I tried understanding the task but got lost in the process. This is why I seek help here on this site. I would like to ask you for guidance and any sort of advice on how to...

Homework Statement The flux density in a single phase core type symmetric(length=breadth=height) transformer is B and flux is Φ. Can we find out the volume of core of transformer if the height of limb is h? Homework Equations Φ = B * Cross sectional area The Attempt at a Solution Can we say...

Hi all, I am interested in rotating convection. Anyone know of any open questions, or where to find research topics in this area? Cheers.

Hey ! Let's say I have a solenoid that is only half-filled with a magnetic core. Now I want to know what is the loss due to Eddy currents. First, I want to find the magnetic field with Ampere's law. With this kind of geometry, I'm not even able to apply Ampere's Law ! have of picture here of the...

Homework Statement ##l/l_0=100## ##S=3 (cm)^2## ##B_r=200μ_0H_c=2mT## ##R=10Ω## No current runs through the feromagnetic core. Calculate the charge ##q## that goes through ##R## from the moment in the diagram to the moment it is removed from the core. Homework Equations 3. The Attempt at a...

I'm an empirical sciences student who loves physics. While studying geology I learned that the core of the Earth is considered to be solid and the reason for that is because the pressure is too high. Although according to my calculations g( gravitational field) equals zero and when you go out...

If a toroidal ferrous core has a number of windings round it and a DC current going through them, would this magnetic core be subjected to a 'shrinking force'? To phrase it more clearly, if the toroidal core was compressible, would it actually get compressed? On the one hand, since the...

I have to couple noise into data cable(cat5) in common mode. I have done this with a CT of 50A/1A, ferrite core. What I have done is, I connected the S1 and S2 of CT to probe of my signal generator and inserted the cable through the whole of CT(ring type). I got maximum of 380mV in the cable...

"As all good textbooks of quantum mechanics have to emphasize and clarify in one way or another, it is critically important that one avoids the assumption that even before the measurement, any of the quantities that may be observed later already have some objective, particular values." Imagine...

The missing element mystery in the Earth's core may have been solved. http://www.bbc.com/news/science-environment-38561076 Lead researcher Eiji Ohtani from the University of Tokyo told BBC News: "We believe that silicon is a major element - about 5% [of the Earth's inner core] by weight could...

1. Homework Statement As shown above Homework Equations *Not too sure if they are relevant. Pretty sure there's more. We have textbooks from the library as references but we still can't quite figure it out :/ Φ = BcAc = BgAg B = Φ/Ac = (Ni/R)/Ac R = lc/(Ac.μ) The Attempt at a Solution...

From, http://www.bbc.com/news/science-environment-38372342 "Scientists say they have identified a remarkable new feature in Earth’s molten outer core. They describe it as a kind of "jet stream" - a fast-flowing river of liquid iron that is surging westwards under Alaska and Siberia. The...