Magnetic fields Definition and 644 Threads

Suppose there is a solenoid near an accelerating electron. The electron must create a changing magnetic field. By Lenz's law, an emf is induced in the coil. One question is, how *fast* is the emf induced in the coil? Is the emf just there instantaneously or does it take time to formulate? And...

Homework Statement Two long parallel wires are a center-to-center distance of 1.10 cm apart and carry equal anti-parallel currents of 9.70 A. Find the magnitude of the magnetic field at the point P which is equidistant from the wires. (R = 10.00 cm). (See Attachment for orientation) I = 9.7 A...

http://s880.photobucket.com/user/nipplebum/media/ATT00001%2010.jpg.html?sort=3&o=0 1. Homework Statement find the unknown poles, draw the magnetic field around the conductor, and determine the direction of the force acting on the conductor. Homework Equations N/a The Attempt at a Solution...

Homework Statement Describe semiquantitatively the motion of an electron under the presence of a constant electric field in the x direction, E =E0x^ and a space varying magnetic field given by B = B0 a(x + z)x^ + B0 [1 + a(x - z)]z^ where Eo, Bo, and a are...

Homework Statement Homework Equations Biot-Savart's law and ampere's law expressing B = mu0 * I / (2 * pi * r) The Attempt at a Solution [/B] I know that for the first drawing, we have magnetic fields going into the page from both of the wires, and we have them being (infinitely) long, so...

Maxwell's equations reveal an interdependency between electric and magnetic fields, inasmuch as a time varying magnetic field generates a rotating electric field and vice versa. Furthermore, the equations predict that even in the absence of any sources one can have self propagating electric and...

How is the alpha decay of a given nucleus affected by the presence of an external electromagnetic field? It's probably an easier question that I think but I've been unable to find a treatment of the tunneling of the alpha particle using WKB method in the presence of a magnetic field.

Sharks are extremely sensitive to magnetic fields, attracted by low end frequencies and repelled or overstimulated by higher/stronger fields. I want to map the spectrum in between using and electromagnetic coil in the water with sharks. I have sharks and a boat but need help building the coil...

I am trying to calculate the forces between a simple sphere neodymium magnet on other iron surfaces and magnets. I did a lot of research but still not sure what equation to use or how to apply them. I found the following equations here (https://en.wikipedia.org/wiki/Force_between_magnets) F =...

Homework Statement An electron with velocity ##\vec{v}_0=8.7*10^4(m/s)## (in the î direction) passing through an area with a uniform magnetic field ##\vec{B}=0.80 T## (in the negative k̂ direction). There's also a uniform electric field in this area. What is the magnitude and direction of...

Homework Statement [/B] Three conducting loops, all with the same resistance ##R## move towards a uniform and constant magnetic field, all with the same velocity ##v##. Their relative sizes can be identified by the grid. As the loops move into the magnetic field an induced current begins to...

Hi, I've been trying to figure several simple things about electric and magnetic fields, their relationship with current. If you could please help me understanding this, it would be really helpful. From what I've read these were presented as natural laws: 1. Changing magnetic field induces...

I was researching the relationship between magnetic dipoles and chemical bonding and I came across a very interesting paper. I'm hoping some of you can shed some light on how magnetic fields are making dissociation of a molecule possible and how to measure it...

Hey all, I'm having some issues with electromagnetism here. Let's say we have a particle with magnetic moment ##\vec{\mu} = \mu_0 \hat{x}## and magnetic field ##\vec{B(x)} = B_0 \frac{x}{a} \hat{x}## where ##\mu_0,B_0,a## are constants. If we assume that the magnetic field ##B_0## is far, far...

I know that magnetic fields create moving charges (an electric current) normal to the plane of the magnetic force lines. I also have heard that magnetic and electric fields create each other in a perpendicular direction to the other (badly worded). Electric currents are moving charges (usually...

Hi All, It is said that iron has a high "permeability" for the magnetic field, it let's the magnetic field pass through it more easily. But it is also said that iron screens the magnetic field? Don't these two contradict themselves? Thanks, Ionel

If I have a some a wire and I took part of it and created a circle. If I want to calculate the strength of the magnetic field at the center of it. I should just use the magnetic field equation for the circular loop, shouldn't I? ## B = \frac{U_o N I}{2R} ## and I shouldn't care about the...

Hi all! ObiWanKenoobi here... it's my first post. My question is on a few levels based on my rudimentary understanding of most things. 1. If you have a ball of molten metal which is tightly compressed to behave almost like a solid... HOW is a magnetic field generated if the ball rotates on an...

Homework Statement Using the tensor transformation law applied to ##F_{\mu\nu}##, show how the electric and magnetic field ##3##-vectors ##\textbf{E}## and ##\textbf{B}## transform under (a) a rotation about the ##y##-axis, (b) a boost along the ##z##-axis. Homework Equations The Attempt at...

My syllabus has point *' 'describe and compare the forces on mass, charge and current in gravitational, electric and magnetic fields, as appropriate" what does this mean ?

What statement about magnetic fields interacting with a moving charge is correct? A) Magnetic fields can’t change the direction of motion of a moving charge. B) Magnetic fields can do work on a moving charge. C) Magnetic fields can accelerate a moving charge. D) The force on a moving charge in a...

Given this diagram: Two wires, having parallel and opposing current flows( Where ## I_1 = I_2 ##), creating opposing and equal magnetic fields near a ferromagnetic object(##F##), since the magnetic field of each wire is not uniform, I'm not really certain how to figure out the magnetization of...

Homework Statement We were asked to use a Hall probe (in units of Guass) to measure the magnetic field strength in 0.5 cm increments away from a wire carrying 4 A of current. As we got further and further away from the wire our B value got smaller and smaller. Eventually they became negative...

This is a continuation of a previous thread in which I was informed my TA was mistaken on an aspect of magnetism. This thread is just to verify another problem within the homework is correct. Other threads will be posted to continue. 1. Homework Statement A) What is the magnetic flux...

So the main reason I'm posting about this problem is that one of the teaching assistants helped me with this problem, but a buddy of mine got something different on part A and part B (Assess). So I wanted to post up here and see what you guys say. 1. Homework Statement The loop in the...

Homework Statement A proton is accelerated from a rest position into a uniform electric field and magnetic field that are perpindicular to each other, as shown, The proton passes through the parralel plates without being deflected, at a constant velocity. When the proton leaves the plates, it...

is it correct that if free floating electrons enter a magnetic field @ a right angle to the field they will take a circular orbit around such field?

Hi guys I was wondering of someone on here could briefly enlighten me on the chemical reactions that would occur with a Teflon Coated high carbon steel hook and a lead sinker while underwater? I am looking into the signals that may or may not be given off by these items both separately and with...

I'm looking for introductory references to the topic of time of tunnelling decay when besides the potential barrier there is also a magnetic field present. I have found a couple of articles about the topic but they treat complicated cases in condensed matter, I'm more interested in the basic of...

Hi, To begin with, I am not a native English speaker and have very limited knowledge regarding magnetic fields and thus want to apologize in advance for probable use of incorrect terms. http:// In the picture above, M represents a magnet. S is a material that is not allowed to be affected by...

Does a superconductor experience any forces acting upon it when it is passed through a magnetic field?

Homework Statement A flexible wire loop has a radius of r = 0.178 m and it is inside a uniform magnetic field of B = 0.332 T. The loop is grasped at points P and Q and stretched until its area is zero. It takes 0.146 s to close the loop. Homework Equations EMF = ∆Phi/∆t Phi = magnetic flux...

1. The magnetic field at point P due to a magnetic source S1 is represented by ==>. Can a bar magnet S2 be brought close to P so that the total magnetic field at P due to S1 and S2 is zero? Explain your answer.2. None3. Yes, this is possible if both fields at point P have the same magnitude but...

As I understand it, you can create a concentrated magnetic field at a specific point by having two electromagnets in a cone shape, both pointed at each other. The cone effectively condenses the field, and is strongest at the region between the points of two cones. Is this understanding even...

Can a cylinder with 1 side open act as a faredey cage (which do not allow passage of magnetic field) when magnetic field are only coming parallel to the curved part

I have no idea how lethal/strong space radiation is, but i do have an idea that most of it is from the sun perhaps? I also know that the prime factor to deflect this radiation is magnetic field and the ozone layer. I think the magnetic field handles only particle radiation and atmosphere handles...

Hello everyone, For the past 4 years I have been working on a new type of musical instrument that fuses together elements from electronic music into the acoustic realm. The instrument consists of 26 strings inside a wooden enclosure that are actuated (or "bowed") by the use of electromagnets...

there are no electromagnetic waves? All I know is that there is a modified version of the Maxwell equations (in differential form) for such a universe, such as (the arrows represent vector arrows): →∇x →B = μ0 →j + μ0 ε0 ∂→B/∂t instead of having ∂E/dt in the last term (which would be the case...

Random thought... Is it possible for a charged particle to travel fast enough, or simply enter a magnetic field at just the right time in the magnetic wave's cycle, to pass through the magnetic field unaffected? If so, what is that calculation. If not, why not. Roy

Does anyone know if they have considered using ultra high efficiency magnets to create an oscillating pulse into the energy of the electron orbital shells? This may in turn break the Coulomb barrier.

Homework Statement 1) Describe and explain what happens to the electron beam on the screen of a teltron tube as the EHT(electrical high tension) voltage increases from 3000V to 3500V. 2)What is the effect of E field on light waves? Homework EquationsThe Attempt at a Solution 1) The beam...

Please forgive me if I am posting in the wrong forum. Also the board limits the length of the title. I wanted to ask about Effect of high intensity electric and magnetic fields on gravity. To begin, 15 years ago this was published...

**Not a homework question. In my professor note, it says that: "If a material causes magnetic field (in parallel direction to the surface charge) below a boundary is not the same as the boundary (in parallel direction to the surface charge) above the boundary, then a surface current is...

Homework Statement There is a counterclockwise current I in a circular loop of wire situated in an external magnetic field directed out of the page as shown. The effect of the forces that act on this current is to make the loop Select one: a. expand in size X b. contract in size c...

I have a question that I can't figure out , there is a toroidal transformer , and the core has an attached part on which another coil is wound. the main coil of the toroidal transformer is connected to a DC source. which creates a static magnetic field in the torus core. the other coil at the...

It could be that I'm misinformed, but I heard electrons at rest have magnetic fields. I thought that magnetic fields required a charge to be traveling at velocity before a magnetic field would arise. If this is the case could someone help me out? If an electron has a magnetic field at rest what...

Since Mars doesn't have a magnetic field of its own due to the cooling of it's core, what if you took a strong magnet from Earth say a superconductive magnet or electromagnet, will the small magnetic field (relative to mars) repel solar radiation, solar flares and other background radiation form...

I know this question has been beaten to death, but I haven't seen a response that clearly (to me) answers the following: 1. Magnetic fields *can do work* on intrinsic dipoles, right? (e.g. two electrons can do work on one another via their intrinsic spin). 2. Magnetic materials can do work on...

Homework Statement This isn't necessarily a problem, but a question I have about a certain step taken in showing that the electric and magnetic fields are transverse. In Jackson, Griffiths, and my professor's written notes, each claims the following. Considering plane wave solutions of the...

Homework Statement Assume that I = 5.0A. What is the magnetic field at point b in the figure? Give your answer as a vector. Homework Equations Ampere's Law - B = (μ0I)/(2πr) The Attempt at a Solution I tried plugging the given numbers into Ampere's Law for point b, which gave me B =...