Magnetic field Definition and 1000 Threads

Hi, I hope that's the correct forum. So I'd like to play around with electronics and magnetism. Meaning: I'd like to build myself a electro magnet and then do some fancy stuff with it. Probably I'll try to recreate this...

Homework Statement The problem asks to find the direction of the magnetic field at point P, which is at the center of 2 separate semi-circle wires that form a circle. The current in each wire flows in the same direction (to the right). I attached a picture below. Homework EquationsThe Attempt...

I understand that magnetic flux density is measured in Teslas or Weber’s per square meter and that voltage or emf is measured using faraday’s law of induction which is E= - N dφ/dt Where N= number parallel fields Φ = magnetic flux (Wb) E= emf (V) What I don’t understand is the time function...

Homework Statement Viewers of Star Trek have heard of an antimatter drive on the Starship Enterprise. One possibility for such a futuristic energy source is to store antimatter charged particles in a vacuum chamber, circulating in a magnetic field, and then extract them as needed. Antimatter...

does the magnetic field created by AC alternate? reverse poles? if so why does a motor rotate the same way every time? does it alternate in three phase as well? thanks, if you want to direct me to literature i would appreciate that, what i have in my motors book talks about the hand rule for...

Homework Statement Example 5.9 in Griffiths's Introduction to Electrodynamics 4th shows us how to find B of a very long solenoid, consisting of n closely wound turns per unit length on a cylinder of radius R, each carrying a steady current I. In the solution, he goes on to explain why we don't...

What happens to the current through a transformer windings if the whole system is under a uniform magnetic field in the direction of the coils and with frequency equal to that of the AC in current? I think the current induced in the primary solenoid should generate a field that would make up...

Hi! I'd like to calculate the rotating magnetic field in a stator The stator is the attached picture. What I understand is the more current = the more rmf, so is there any equation / formula to calculate the rmf as a result of current? Thank you

Hey, I need a little help I know in a DC motor there are permanent magnet and also coil So my question is, what is the equation to calculate the magnetic field strength in a stator dc motor compound?

When capacitor is leaking ie, when charge is leaking or when it is discharging then will there be any magnetic field between the parallel plates of capcitor?

Is correct to calculate the resistance of a semiconductor sample in a magnetic field with ohm’s law?

Homework Statement Two long wires, one of which has a semicircular bend of radius R, are positioned as shown in the accompanying figure. If both wires carry a current I, how far apart must their parallel sections be so that the net magnetic field at P is zero? Does the current in the straight...

Homework Statement Homework EquationsThe Attempt at a Solution I know how to solve this problem . I just need help in interpreting the language of the problem as to what is given and what is required to calculate . 1) Is 30° the true dip and we are asked to calculate apparent dip OR 2) Is...

Homework Statement [/B] A radio transmitter radiates isotropically at the frequency of 90.8 MHz. The peak magnetic field at a receiver, 9km from the transmitter, is ##9x10^{-10}T##. Calculate the maximum amplitude of the induced emf in a 12 turn coil with area A = ##90cm^{2}## at the receiver...

Homework Statement each wire carrying 10 Amps a = 0.3 meter point o located in the center Homework Equations B = permeability constant * I / ( 2 ##\pi## r) r = distance between O and the wire r perpendicular to B and I A = carrying current into the page B and C = out of the pages The...

Now I know that the magnetic field is made of photons iam trying to understand how it creates the attraction of force. I am not sure if its true or not I theorized that the magnet emits photons towards the material for example Iron and it turns one end to positively charged and the other end...

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, we have done an experiment where we have to measure the resistance of a sample of Ge doping-p and how it changes due to a magnetic field perpendicular to the sample with a costant current. We have found that R(B) has a quadratic trend (we have fit the dates with y = a[1+b*B^2] with a and b...

Homework Statement The question is in the attached document Homework Equations Newton's second law states that F=ma Charged particle in magnetic field experiences F=Q ( v X B) The Attempt at a Solution Since the charge 'Q' is constrained to move along a path in xy-plane in such a way that the...

Hi, I would like to raise a question about Role of magnetic field while formation of small to medium scale stars emerging from nebula ?

When we see the aurora moving rapidly are we effectively seeing the Earths Magnetic field moving ? Is that part of the explanation for the morphology of the aurora and why they never look quite the same?

Hopefully, a simple question with a simple answer. I have a flat magnet (assume infinite long and wide) with a field strength at the surface of (for simplicity) exactly 1Tesla. What will the field strength be (in air) 1mm away from that surface? I know approximates to 1/r^3, but 1/0.001^3 =...

Hello, I have seen that biot savart's law works for infinitely narrow wires: "The formulations given above work well when the current can be approximated as running through an infinitely-narrow wire." When I wanted to derive the magnetic field of a solenoid, I had to do this substitution...

Homework Statement Calculate the time-dependent magnetic field intensity B(t) at an axial distance r from a long, thin straight copper wire that carries a sinusoidal current with an alternating frequency of 50 Hz and a maximum amplitude of 0.5 A. Homework Equations I = Asin(\omega t) B =...

Thank you for reading my post. I was thinking about induced emf and magnetic flux and I realized I have a huge misunderstanding, but I don't know exactly what it is. Below I will list 4 statements which I logically know cannot all be simultaneously true. Can you please tell me which one(s) are...

Homework Statement Homework EquationsThe Attempt at a Solution When the circuit moves creates magnetic force that moves the some charges in the wire and that is a current. That is what i thought. F = Q.v B sin theta B = ( permeability Of vacuum* I)/(2pi.r) But how to find the I? Thank you...

Homework Statement A magnetic field of 1.4 T [N] is 4.0 m wide. A very long wire crosses the field. a) If the current in the wire is 2.0 A [W], find the magnetic force on the wire. b) What will happen to the force on the wire if i) The wire is rotated slightly in the horizontal plane? ii) The...

Does a ferromagnetic body moving through an external constant magnetic field obtain an induced magnetic moment? If so, can this induced field be detected? Which equation describes it? Thanks!

When current flows through a copper wire, for example, a magnetic field is produced. What is the polarity of that field? I've seen an example with special relativity and how a positive charge would be deflected. Does that mean the field is negative to a stationary object? Every video I watch...

I don't understand something. At the center of N circular loops, the magnetic field is μ_0NI/2a. And that for a solenoid is μ_0nI. Why are they not the same when the number of loops is large and the length for the solenoid is long?

Homework Statement A long wire with a current changes direction by 90 degrees. Calculate the magnetic field at the point at a perpendicular distance of S from the wire before it changed direction and a distance of T from the segment of the wire after it changed direction. Homework Equations I...

This is question that can't really get a precise answer without significant modeling or experimentation, but I'm wondering what folks' intuition might be on an answer to the following setup + question: Suppose there is a steel tank made of steel pipe with walls about 0.25 cm thick, internal...

Hi guys, a solenoid coil 10x4 mm needs to be moved along the vertical axis of a strong magnetic field (up to 14 Tesla) generated by a superconducting magnet. The coil must be contained into a classical probe for NMR spectroscopy, and moved vertically inside that probe. The main issue I am facing...

Good day All, I have a confusion in my mind and i hope to clear it If we use the Amper law to calculate the magnetic field outside the cable, the value would be 0 because the electric current inside the amperian loop is equal to 0, but in case we apply the Biot savart law to calculate the...

Ok so I haven't been on here for a while but I can't seem to find an answer to my question anywhere and really need some help! So I not only am an electronics hobbies but I have fun installing car audio systems as well. The problem I am running into is that I would like to run an alt wire...

Homework Statement Describe the magnetic field you would observe if two coils were connected with magnetic fields pointing in opposite directions. Homework Equations No equation The Attempt at a Solution If the magnetic field was pointing in opposite directions, would it mean that it would...

The equation of motion for a charged particle with mass ##m## and charge ##q## in a static magnetic field is: ##\frac{d}{dt}[m{\dot{\vec{r}}}]=q\ \dot{\vec{r}}\times \vec{B}## From this, we can see that ##\frac{d}{dt}[m\dot{\vec{r}}-q \vec{r}\times \vec{B}]=0## and so the following quantity is...

Homework Statement Three very long parallel conductors situated in the air make a direct-symmetrical 3-Phase system. The conductors pass through the A B C points of the triangle of side ##a##. The currents in the conductor form a direct-symmetrical 3-Phase system. Effective values of currents...

Hello With a normal magnet, we use energy to position a particle away from the magnet and then the magnet does work and moves it close to the magnet. Is there any way to have such movement being rotational? Ie to uae energy to move a particle or point clockwise and then the magnet will move it...

Is it possible to direct or confine field lines to be shaped like a laser? I know there are magnets such as neodymium cones that direct field lines through the tip but they don't seem to have the amount of pull as I'm looking for. If there isn't, is there anyway to amplify the power? Maybe align...

Hello, I am wondering if one can create a magnetic field which can be seen by a human eye? I have learned that light is nothing else but electromagnetic field with a wavelength between 400-800 nm. Colours correspond to different wavelength within the above spectrum. So isn't it theoretically...

I attached the image of the problem . I'm sorry if it is unreadable. It essentially says that there is a parallel plate capacitor with a uniform electric charge in the space between the plates. And a uniform magnetic charge is in the space between the plates which is produced by another...

Hi everyone, I am currently working on a project in Physics analyzing the possibility of magnetic fields protecting against radiation particles such as fully ionized nuclei or electrons. I wrote a code in Matlab that simulates a 3-D magnetic field based on a combination of wires and wire loops...

Homework Statement Consider a solid spinning sphere of negative charge in a non-uniform magnetic field: http://d2vlcm61l7u1fs.cloudfront.net/media%2F2f8%2F2f840122-3d7f-4af3-98a7-efa9b2e7d26a%2FphpBOhfaK.png (the rotation illustrated at the top is supposed to be counter-clockwise). What...

Homework Statement Homework Equations Magnetic Field of a Current Loop The Field of a Long Straight Wire The Attempt at a Solution Sorry ! I'm so stupid that i couldn't figure a way to solve this exercise. I don't know how to start with those two equations. Please help me !

So i was just wondering if a satellite's circuitry could be affected by the Earth's own magnetic field inducing a current, if it was moving through it quickly enough (the space station for example), and how it might mess with it? Also considering a satellite is a big hunk of metal, could passing...

Homework Statement x represents the distance between the wire and P. The wire has infinite length. What is the magnetic field created by the wire at P? Homework Equations B=μ0I/2πr The Attempt at a Solution I thought the the first part of the wire creates a field equals to μ0I/2πx (directed...

First let me say THANK YOU to anyone who reads my work and tries to help, I know it can be a pain to decipher the work of others (although I've tried to make it as clear as possible). If any part is unclear I will try to explain it. I cannot for the life of me see any flaws in the argument...

By relativity+coulombs force, I worked out that the (magnitude of the) magnetic field of a charge Q moving at speed V should be (ϒVV/c2)Q/(4πε0r2) or in terms of mu, ϒVμ0VQ/(4πr2) (where the distance r is measured normal to V). When I google the answer I only find the same thing but without the...