Magnetic field Definition and 1000 Threads

This question is motivated by Problem 7.12 in Griffiths Electrodynamics book. I have not included it in the homework section, because I have already solved it correctly. However, I question whether my solution which agrees with the solution's manual is correct. Relevant Equations: $$\Phi =...

What is/are the potential or theoretical effect on electricity due to reversal of planetary magnetic field? Would circuitry continue to function or would knowledge and understanding need re-evaluating as a result of a reversal of our magnetic field on planet Earth? Note: this is not a homework...

Hello, Today I am wondering if anyone can help me quantify the strength of the magnetic field created by a permanent cylindrical magnet. I have been able to find equations online for the strength of the field within the z axis, (ie. the longitudinal length) but I would like to know the strength...

I know that the field inside sample is a combination of the demagnetizing field and whatever applied field you may have. So these two fields together influence how big a field you need in order to magnetize the sample.

Would this also be correct? Or is there something wrong with it? I appreciate all your responses! Snarlie

I want to know the total energy contained in a magnetic field due to a long wire (just consider a 1m segment) as a 1amp current is turned on starting at time zero. I'm assuming zero turn-on time for convenience. At t=0 the cylindrical field is formed and I wish to know the total energy as a...

Homework Statement: The distance between two parallel long wires, carrying currents equal to i and 3i respectively, is d as shown in the picture. What is the distance from the wire carrying the current i at which the magnetic field is zero Homework Equations: guess biot-savarat Being two...

So far the best I've been able to come up with is to use ##\vec{B} = \mu_0 \vec{H}## which gives me i_c = H 2\pi r j_c = \frac{H 2\pi r}{\pi r^2} = \frac{2H}{r} \therefore B = \mu_0 \frac{r j_c}{2} I'm fairly confident this is just terrible math and physics on my behalf but I'm struggling to...

Hi all, so I had this problem and on the exam and I got a solution but I had an mass-term in there which wasn't given. I used Farraday's Law of Induction to get the Voltage induced. Then I used ##rho* \frac{A}{4a} ## for the resistance and divided the Voltage by that to get the current. I then...

Summary: Can a rotating AC Magnetic field induce movement in a static DC Magnetic flux? I'm designing a control panel, and the customer has asked us to reduce the EMC as much as possible; there are no drives, or other noise creating devices, just AC circuits. I thought a good starting point...

I thought that a nearly parallel entry path would result in a helix of very small, but constant, radius. I would not expect the electrons to focus at a point, but continue along the infinite helix. What have I missed?

Problem Statement: It is possible to describe synchrotron radiation as caused by a loss of electrical charge of relativistic particles that are moving in a magnetic field? Relevant Equations: E = mc2 An Italian expert of black hole M87 (Elisabetta Liuzzo) explains that the expected axial...

I want to render the Earth’s Magnetic field in a software and simulate solar wind electron interaction with it. How do I calculate the magnetic strength and vector orientation at each point around the Earth up to thousands of km? Is there a formula? Or do I need to download a vector field from...

Hi, second problem in one evening, I'm sorry! But I'm also not quite sure if I did this one right. I had thought I need lenz's law but there is no current before entering the field so I just use the induced Voltage? My approach: ## V = \frac {B*A}{t} ## ## IR = \frac {B*A}{t} ## and ## A = v*t...

I went with R=mv/qb, thus -> 6.64e-27*35.6e3/2*1.6e-19*1.8, and got 4.1e-4 m (metres), so diameter is 2R, 8.2e-4 m, as an answer, the reference site gives 3.95e+10 m as the answer, who's right here?

Hi, at this moment I'm trying to figure out one thing. I have a solenoid with a core that has an empty middle, the flux normally loops back around the outside of the solenoid to the other side where it enters back into the core. I need to route this field between the two ends of the solenoid...

Do solar wind electrons turn left and positively charged ions turn right if they are interacting weakly due to long distance with Earth's magnetic field and fail to complete a loop for the electrons that are on the left of Earth and ions on the right? I assume electrons on the right and ions on...

Tried to find the resultant force, but I can't see how the magnetic field affects. I used Faraday's law to find the the diferece of potentials in the plate Wich should be B.d.v, where v is the vertical velocity of plate, but there were not given the resistance or resistivity to relate with the...

a) We can solve for acceleration by looking at FNETy FNETy = FE (G is negligible) FNETy = m * a The mass (m) of an electron is 9.1093836 x 10-31 kg. The elementary charge (q) of an electron is -1.60217662 x 10-19 C a = ε * q / m a = (4.0 x 102 N/C * 1.6022 x 10-19 C) / 9.1094 x...

As I said my goal is to derive the equation ##\tilde{B}^k(\vec{q})=-i\varepsilon^{ijk}q^i\tilde{A}^j_{cl}(\vec{q})## As far as I know, the magnetic field is defined using the potential as ##\vec{B}=\vec{\nabla}\times\vec{A}## Then in equation 6.6 they define ##A^\mu(x)=\int...

Problem Statement: Potential difference is the difference in the quantity of charge in both potentials. How does the magnetic field creates this difference of charges ? Relevant Equations: None Hi, I was reading electricity and found that the difference in potential of both end is the...

For the front wire, I got the magnitude of the magnetic field in terms of the magnitude of the magnetic force, the current, "l," and the "theta". I am unsure how to proceed because I thought that the magnetic force is independent of any other forces. I am also just lost in general. Any help...

Why a magnet bar would become aligned with the external magnetic field while a magnetic moment would precess around the external magnetic field?

I started with the first of the relevant equations, replacing the p with the operator -iħ∇ and expanding the squared term to yield: H = (-ħ^2 / 2m)∇^2 + (iqħ/m)A·∇ + (q^2 / 2m)A^2 + qV But since A = (1/2)B x r (iqħ/m)A·∇ = (iqħ / 2m)(r x ∇)·B = -(q / 2m)L·B = -(qB_0 / 2m)L_z and A^2 =...

All i could think is that the z component of velocity will remain unchnged as there is no force in that direction.And for the x and y component can we imagine the helical motion as a superposition of a circle and a straight line.So for x and y component can we solve for a particle moving in a...

I know that we need to use some boundry condition both on the a radius surface and the b radius surface and somehowuse the superposition on them both, the boundry condition most be for the tangential and the radial part, the only things I got is that i don`t know how to produce a magnetisation M...

This is a very basic issue but really important as well. The rectangular loop has length ##l## and width ##h##. I have seen the argument of neglecting the encircled sides of the loop because ##h << 1## while using Ampere's law to calculate the magnetic field flowing over a plane. I find this...

I read Wikipedia's description of how a plasma ball works. Question: What kind of energy is the "radio-frequency energy from the transformer"? Is in the form of electric field energy, magnetic field energy, or both? Thank you! (from Wikipedia)... Although many variations exist, a plasma lamp is...

So, as it says in the title, I am trying to calculate overall voltage induced in a coreless coil in the cases of it being stationary and moving in an alternating magnetic field. To go more into detail, I would like to create a mathematical model of a coil in an alternating magnetic field that...

I tried to look once at the zy axis and saw a two infinite capacitors with fictive charge density of M on the upper plane, and -M in the lower with a distance of h from each other, the two capacitors saparated with d in the y axis, but when I look in xy axis there was 2 another capcitors the...

$$V = \int \left(\vec{v} \times \vec{B}\right) \bullet \vec{dl} - \int _S \frac{\vec{dB}}{dt} \bullet \vec{ds}$$ From the statement I know that: B⊥v, (B x v) // dl and B // ds. $$V = \int vBdl - \oint _S \frac{dB}{dt} ds$$ v is the speed with which all the segments dl are aproximating to the...

Assuming that you can create a proton current. For example, the current of ionized hydrogen is analogous to a conductor. Question! Will a magnetic field be created around a conductor with a current of protons? By analogy with the magnetic field of electrons in a conductor.

v = sqrt( (2 * charge of proton * 3000/e) / (mass of proton)) v = 1.893986024 x 10^`15 r = ( (mass of proton) * (velocity) ) / ((magnetic field) * (charge of proton)) r = 24715769.68 m Anyone please help

M1(50,000)/q (0.4) - M2(50,000)/q (0.4) = 0.025 Is there a special charge for singly charged ions?

m = 0.005 q = -70 x 10^-6 c v = 30,000 m/s Since there is no movement vertically Fb = Mg So, q . V . B = mg So, (70 x `10^-6) . (30,000) . B = (0.005) . (9.8) So, B = 0.0233333 or ~ 23 MT

emf = dΦ/dt = (B*A)*d/dt = B(dA/dt), dA/dt= L*d/dt(vt) = L*v, emf = B*L*v per coil Since there are 25 loops the total emf= 25(vBL) This is where I'm am stuck. Would I assume that B is 24 uT, the velocity as 3m/s , and the length as 1mm? If so I would get ∆V as 1.8*10^-6.

V=I*R 6v=I*(0.6+0.9)ohms I=4amp B=100*(uo)(2N)(I)/L * 1/2 I think since the wire is double wrapped, we multiply the equation by 2, but since we are looking for the magnetic field at the end of the wire we also have to multiply the equation by 1/2 I=4A, uo= 4pi*10^-7 2N/L turns per unit...

F = ma F = (6x10^-6) * 8 F = 4.8 * 10^-5 F = QBVsin(theta) F/(BVsin(theta) = Q (4.8 x 10^-5) / (5 x 10^-3) (4000) (sin(37)) = 3.98 x 10^-6 ~ 4 uc <---- THE RIGHT ANSWER IS -4 uc

Here is a little thought experiment related to magnetism and a perplexing question regarding its physics. Suppose we have a long cylinder of transparent plastic, and we press fit and then cement a circular magnet in one end of the cylinder with its north pole oriented into the cylinder. We also...

Recently I am learning about electrodynamic radiation and its various types, and it occur to me that since the form of the magnetic field created by the dipole radiation is some combination of cos(wt), 1/r, and cos(kr) (take the approximation of r >> c/w) Therefore, if there is a metal placed...

I need help with the problem above

F=ILB F=(48)(.76)B F/36.48=B I am stuck at how to find F, is there a different formula I am missing?

So I'm kinda stumped. I'm assuming that since ##\vec{m}||\vec{B}##, the x and y components of both are zero. But I'm unsure how to take this further.

I'm confused what's meant by a uniform surface current density since this plane has a thickness, It would need a current density distributed through its cross sections, I thought.Edit: I tried solving with proper LaTeX and all my steps, but it looked awful. For outside, I got B=µ_0jd/2. for...

I am new to the site I apologize If I am posting incorrectly or doing something wrong. I need help figuring out how to increase magnetic field density (gauss/tesla's) extending from a magnetic object's surface, most magnets magnetic density is all in the center. I need this in order to induce a...

Hello, Let's imagine we have an infinite plane (or large enough compared to the region of interest and measurements) pierced in normal direction by magnetic field B which is uniformly distributed but time varying. For the sake of simplicity we'll presume the magnetic induction is linearly (and...

A charge is entering magnetic field perpendicularly! Griffiths says it motion will be circular! But it is accelerated so it must radiate energy and it's motion should be spiral inward?

I might be a slow learner, but am still trying to understand the difference between field lines and vectors. I've got that magnetic field lines are symbolic and that the directional arrows applied (from north to south) are a convention. But see the attached image. The field lines form a closed...

(a) Let's say the loop has fallen ##y## from its initial position. Then the magnetic flux is ##B_{0}w(h-y)## and the induced voltage is ##\mathcal{E}=B_{0}wdy/dt##. Since this voltage is positive, the current flows clockwise. (b) ##I=\frac{\mathcal{E}}{R}=\frac{B_{0}wv}{R}## (c) The force on...