Magnetic fields Definition and 644 Threads

Homework Statement This is just a conceptual question that I've been personally wondering about. So light has a magnetic field wave perpendicular to an electric field wave. I don't quite understand the magnetic field wave though. I thought that magnetic fields were not supposed to have a...

I've checked Wikipedia for answers but can't find any. I'm learning electromagnetism in school now. I don't know why this happens and so I can't understand the lessons! Can anyone tell me why? Thx :)

Like to know the behavior of MR Fluids when rotated inside a hollow shaft subjected to magnetic fields.. Could anyone please help

I was watching this video here: http://www.youtube.com/watch?v=bzRee_yHeOs&feature=g-hist and was wondering what kind of metal they used to concentrate the magnetic field?

Basically I just wanted to know how magnetic fields work when a highly Permeable material is placed close to a magnet. I mean normally a magnetic field as far as I know expands out it all directions whether it is from a wire or a coil or a magnet, but what happens when a Permeable material is...

What do you propose as a quick DIY method for measuring magnetic field flux densities around ~2T?

Hey guys, I have a simple conceptual question: Let's say I'm moving a loop of wire into a constant magnetic field that points into the page. The wire needs to create a magnetic field out of the page to oppose this previous change in flux. The typical question would be which direction does the...

Homework Statement An electron and a proton each travel with equal speeds around circular orbits in the same uniform magnetic field ( I tried to attach a diagram...not sure if it worked but I've described it anyways). The field is into the page on the diagram. Because the electron is less...

Hi, I am doing some research into magnetic fields and I have a question. Are strong oscillating magnetic fields safe for human bodies? I am referring to the type of magnetic field in a speaker just a lot bigger. If you have any info that would be great.

Homework Statement If a flat wire lies in a north-south direction will the MAXIMUM magnetic force be felt if the field lies either in a east-west direction OR an up-down direction (i.e: ppd to the direction of the current?)?? Homework Equations The Attempt at a Solution I know...

Hi all, I'm currently working on a game about magnetism and have run into some problems. I'm hoping that you guys here will be able to help me with it. I've been reading about magnetic phenomena on the net, and one of the things I've found is that the magnetic force exerted between two...

I hope this isn't in the wrong forum, it's not a problem, just a conceptual question for physics 2. I have a few questions that I cannot find answer for in my physics book or online. 1) Why does moving a charge parallel to the magnetic field result in zero magnetic force? Is this quality...

Since we have such a strong magnetic field around the earth, why does it not interfere with smaller magnetic fields we use such as medical equipment, radio wave progagation and other things that creates an magnetic field ?

Homework Statement A 2.60-N metal bar, 1.50 m long and having a resistance of 10.0 ohms, rests horizontally on conducting wires connecting it to the circuit shown in the figure . The bar is in a uniform, horizontal, 1.60-T magnetic field and is not attached to the wires in the circuit. What...

Homework Statement A particle with a charge q and kinetic energy K travels in a uniform magnetic field of magnitude B. If the particle moves in a path of radius R, find expressions for (a) its speed and (b) its mass. Homework Equations K=1/2mv^2 and R=mv/qB The Attempt at a Solution I...

Homework Statement A solid cylindrical conducting shell of inner radius a = 5.3 cm and outer radius b = 7.9 cm has its axis aligned with the z-axis as shown. It carries a uniformly distributed current I2 = 7.1 A in the positive z-direction. An infinite conducting wire is located along the...

Are both velocity and "jerk" of charges responsible for magnetic fields? It is commonly believed that changes of electric fields cause contributions to a component of the magnetic field and that changes of magnetic fields cause contributions to a component of the electric field. In the case...

It has been stated that a charged particle in the vicinity of a magnetic field experiences a force given by F = qV x B, which states that there is no force when its velocity is zero. It also shows that only the particles direction can be changed, not its kinetic energy. My question is this...

If a charged particle passes through a magnetic field it will be deflected according to the right hand rule, i.e. VxB. What if the magnetic field lines are parallel to the velocity of the particle? Will the particle still be deflected?

Homework Statement An ion with a charge of +1e enters a region where the electric field produced by parallel plates at 630V separated by 7.0mm is at right angles ot a magnetic field B=450mT. The ion moves a straight line. Find the magnitude of the electric field and the speed of the ion...

I am interested in replicating Bob Beck's work in the attached PDF document, dating back to 1978. After building a variety of coils Beck was able to demonstrate EEG entrainment with a 9-foot coil and by broadcasting an amplified Schumann Resonance frequency. The idea would be to interface said...

Dear PFs I am facing a problem with finding a good Hall-effect magnetic flux sensor which should be fixed in the top of a probe working in a very intense magnetic field. The probe must be aligned to a certain degree with respect to the direction of the main field. The requested alignement...

Homework Statement Consider a general point on the line joining the two wires and a distance d away from the mid-point O. By summing the magnetic field due to currents of magnitude i flowing in both the wires which are non-zero, show that on the line joining the two wires, the magnetic field...

Homework Statement (i) Find the magnitude and direction of the magnetic field at the point O located at a distance D = 10 cm from a wire carrying a current i = 1.0 A directed into the page, as shown in the attached drawing. (ii) A second wire, identical to the first, is placed a distance D...

what do we mean exactly by visible light? Since light is oscillating electric and magnetic fields, and both electric and magnetic fields are invisible, what do we actually see? is color the wave itself?when we see colors do we see the waves themselves and if their wavelength were bigger would...

Homework Statement there is a cylindrical area in xy plane with a magnetic field (into the plane) that changes with time like that: (dB/dt)=δ the magnetic field outside the area is 0. the radius of the cylinder is a. we pick a string in the circle with lentgh L which is smaller than the...

In the example diagram I have provided how can the counter EMF produced by the conductor moving through the magnetic field be determined? I am assuming the field is uniform and that the velocity and current in the wire is constant. My logic tells me that there is no net flux cut by the...

I got this electromagnetic field detector that can measure magnetic field (B-fields) of Alternating Current of 60 Hz. Supposed after getting the 2 wires together and the magnetic field canceled and reading lowered from 10 milligauss to 1 or 0 milligauss. Does it mean getting a meter that...

In preparation for an upcoming physics exam I have been going through some past paper questions. This question is from the multiple choice section of the paper, so while I can check the answer there is no source from which I can see it being worked through. Homework Statement An aircraft...

Hi, I have a hard time finding a justification that electric and magnetic fields are still orthogonal when presented in complex form. As far as I know the notion of orthogonality for complex vectors is not as intuitive as the one for real vectors. Notably, \vec{x}\cdot\vec{y}=0 does not imply...

I'm just trying to get my head around how magnetic fields attract and repel each other, Say you have two loops of current a distance d apart, the current through the top loop is counter clock wise when looked at from above. If the current through the top loop is slowly decreased, a...

ok so you have a current flowing through a wire that induces a magnetic field, the direction of which is given by the right hand rule. my question is: WHY is there an induced magnetic field? what actually causes it? thanks. (fyi I am in classical e&m right now)

Hi, Question: There are two long, parallel vertical wires, each carrying currents in the same direction. The wire passes through a horizontal sheet of card. The card is removed and one of the two wires is free to move. Describe and explain the changes in velocity, and in acceleration of...

Homework Statement Write down the equations for the real electric and magnetic fields for a monochromatic plane wave of amplitude E(subscript 0), frequency omega, and phase angle phi=0, that is a) traveling in the negative x direction and polarised in the z direction b) traveling in the...

Homework Statement In my physics lab, we were asked to connect an unpowered solenoid to an oscilloscope and then move a magnet through the solenoid and observe the changes in voltage on the oscilloscope. First we were asked to move the north pole of the magnet into the solenoid and then the...

Hi, I have 2 coils arranged next to each other. One of them is used to generate alternating magnetic field at several Hz, and the other one also generate alternating magnetic field but at higher frequency (several kHz). Are there any magnetic sensors that can measure only the...

1)A wire is carrying a current, i, in the positive y-direction. The wire is located in a uniform magnetic field, B, oriented in such a way that the magnetic force on the wire is maximized. The magnetic force acting on the wire, FB, is in the negative x direction. What is the direction of the...

I have attached the drawing. Why is the magnetic field at the location negative and not positive? When I do the right hand rule I point my thumb in the direction of the current and wrap my fingers around the wire. My fingers pointed up for each wire which should be positive z not negative, but...

Homework Statement At a certain point on the Earth's Surface the horizontal component of the Earth's magnetic field is 1.8 * 10^-5 T. A straight piece of wire 2m long and 1.5g lies on a horizontal wooden bench in an east-west direction. When a very large current flows momenterily in the wire...

I can't figure out what is the motion of a charged particle at rest at origin in a constant uniform magnetic field when it is subjected to an oscillating electric field starting t = 0. I need to find the equations representing its motion.

Homework Statement Suppose your physics lab class lasts for a very long time - long enough for you to wind a semi-infinite solenoid. (That spool of copper wire is the gift that keeps on giving.) What is the on-axis magnetic field at the end of the solenoid closest to you (ie., not at...

Hello, I'm in 9th grade looking for some interesting topics to do my science experiment on this year. I'm particularly interested in how magnetic fields affect photons. I know photons are electrically neutral but I'm looking for some "what if?" types of questions. I think somehow being able to...

In electrodynamics, the gauge potentials are not directly measureable, but components of the field strength tensors, which are the electric and magnetic fields are. But why are the electric and magnetic fields, the components of the curl of something not-measureable (the gauge fields)...

Hello everyone, I hope this is in the right section. if not i'll be happy to move it. Anyways i have a few questions about general concepts so this may be a lengthy one. Any and all help is REALLY appreciated. I have attached two photos of something explaining the creation of a magnetic...

Using Magnetic Fields in Place of Heat Shielding Joshua “FireStorm” King Note: All Graphs are in SI base units Note 2: I strongly recommend downloading the document version of this post as the equations are actually readable there. RTF Format: Docx Format: Introduction: The Problem I'm a real...

¿ Can diff. EM frequencies create diff. magnetic fields with diff. properties ? I understand that a magnetic field is generated via moving charged particles . Electricity and magnetism are linked through electromagnetism . Electromagnetism can be in different wavelengths and frequencies but...

Homework Statement A) Find the magnitude of the net magnetic field at point P and point Q B) Reverse the directon of the current for the wire on the x-axis Homework Equations B = μ0I/2πr The Attempt at a Solution Solution attempt attached. Only attempted part A, since I probably won't get...

Where did the formula r=mv/Bq come from in my answerbook for my grade 12 physics? Thanks.

Hello, I am curious as to how this works exactly. What I have a question regarding is having multiple solenoids within 2 inches of each other. Say we have a square, and on each corner is a solenoid standing up, so the corner is center on the axis going through the solenoid. All of them have...

Hello again PF, I've been doing some light reading on different magnetic fields of different gas giants, and what was really fascinating is how different Uranus and Neptune's fields were from Jupiter's and Saturn's, due to their different mass and composition? What I read was that both of...