Magnetic fields Definition and 674 Threads

a long wire is bent into a hairpin as showqn in the figure. If the wire carries a current of i = 1.5A a) what is the magnitude and the direction of B as point a? b) at point b very far from a? assume R = 5.2mm a) for a since R is constant s = 2 pi R B = \frac{\mu_{0} i}{2R} and this...

The north and south ends of two magnets are placed facing each other so that they create a uniform magnetic field. A small metal object passes through the field with a constant velocity. Sketch a graph to show how voltage varies with time for the path of the object from t=0 to t=3 t=0 object...

confused on Magnetic fields! Hello everyone, we just started a chapter on magentic fields due to currents and I'm pretty lost. I'm looking at the homework and its making no sense to me.. I read the section and yet its not helping either. It gives lots of formulas but doesn't really explain...

Anyone have any good references or insights on excitons; excitons in bilayer semiconductors; excitons in high magnetic fields (fractional quantum Hall regime) or Bose condensation of excitons ? I'm going through the literature but want to make sure there isn't something useful out there that...

A question concerning atoms in magnetic fields: Why does the LS-coupling break down in a strong magnetic field (Paschen-Back effect)? I have until now only gotten this stated as a fact, but if anyone could give a few arguments it would be appreciated. Why aren't the individual components of...

Hi a short question: can I use the superposition principle for magnetic fields? reegards tem

I ran across this article in "Newsweek-Next Frontiers" about stimulating neurons directly by firing large magnetic pulses to specific locations in the brain: Address: http://www.msnbc.msn.com/id/9557716/site/newsweek/ Well, I can imagine a much more "accurate" device which can affect...

can a faradays cage be used to block external magnetic fields from interfering with the contents of the cage?

Hey I'm wondering if someone can help me out with this question. Q: In order to measure the magnetic fields produced by the power lines carrying 50Hz alternating current, a coil consisting of 1500 turns of area 5cm^2 as constructed. Suppose that there is a single power line carrying a...

would increasing the speed at which magnet passes through a coil Increase,Reduce or does not change the amount of electromagnetic induction? cheers personally I would go with increase but want to see if I am right

Hello, I've just entered this forum and... the world of Physics. And I already have tremendous enigmas. Let's start with this. Oersted revealed that a static magnetic field exists in the nearby of a current loop. Now "current" means "moving electric charges" and e.m. theory states that a moving...

If a charged particle moves at a constant velocity in a straight line through a region of space, is the electric field and/or magnetic field in the region zero?

I don't understand this question at all- could someone please help- at least giving me a starting point- thanks A wire, of length 70cm is placed into a magnetic field of strength 0.001T. If the wire carries a current of 5 amps 1/ Calculate the magnitude of the forces on the wire if it is...

yes well i think i will get right to the point on this one, my first question is this i heard about these group of people that live neer the Hoover dam, specifically, neer the output power lines, that are complaining about electromagetic radiation from the powerlines, magnatisim. now my first...

Hey all I was just wondering if anyone knows how to figure out these two questions. 1) The difference in potential between the cathode and the anode of a spark plug is 1.0x10^4V. What energy does an electron give up as it passes between the electrodes? This one I am really pretty clueless...

i have a question that i need some help with: at time t1, an electron is sent along the positive direction of an x axis, through both an electric field E and a magnetic field B, with E directed parallel to the y axis. Figure 28-34 gives the y component Fnet, y of the net force of the...

"A magnetic field has a magnitude of 1.2 x 10-3 T, and an electric field has a magnitude of 5.1 x 10^3 N/C. Both fields point in the same direction. A positive 1.8 µC charge moves at a speed of 3.2 x 10^6 m/s in a direction that is perpendicular to both fields. Determine the magnitude of the net...

Please help me with magnetic fields - how can i find its direction?? The drawing shows two wires that carry the same current of I=85.0 A and are oriented perpendicular to the plane of the paper. The current in one wire is directed out of the paper, while the current in the other is directed...

I am trying to develop a model about how solar storms interact with the magnetosphere. In the picture attached, assuming that the magnets are fixed to their positions, how will the resulting magnetic field look like? Will the field lines of the larger magnet be deflected up and downwards...

I want to calculate the magnitude of a net magnetic field. I've got two long wires. One that carries a current of 6.2 A in the positive y direction and the other wire has a current of 4.5 A in the positive x direction. Is the resulting magnetic field the resulting vector when these fields are...

given that B = (6x, -9y, 3z) find the total force experienced by a rectangular loop in the z = 0 plane. 1<x<3 1<y<2 i used the torque equation, but my question is if i have to do the integration for all 4 sides of the rectangle. T = int(dl cross B)

Can anyone point me to some reference as to how magnetic fields are produced in the inter stella medium please.

Hi First, I´m new in this forum so I´m not sure if I´m posting in the right place. If I don´t...well, sorry. Then my question...I´ll try to explain. I´m playing with an inductively coupled RFID-reader and smart labels. Holding the smart label 90 degrees with respect to the antenna, the...

Suppose the light bulb in Figure 22.4b is a 60.0-W bulb with a resistance of 240 W. The magnetic field has a magnitude of 0.40 T, and the length of the rod is 0.60 m. The only resistance in the circuit is that due to the bulb. Minimally, how long would the rails on which the moving rod slides...

A square coil and a rectangular coil are each made from the same length of wire. Each contains a single turn. The long sides of the rectangle are twice as long as the short sides. Find the ratio tsquare/trectangle of the maximum torques that these coils experience in the same magnetic field when...

Two oppositely charged objects exert a force of attraction of 8.0N on each other. What will be the new force of attraction if the objects are moved to a diustance four times their original distance of separation? i did this.. F=kq1*q2/4r 8.0N=9.0x10^9 (1)(1)/4r r=1.125x10^9m how can you...

help pls! since electrons cr8 a magnetic field due to their spin, shouldn't atoms be magnetic? o0

I desperately need help, for I am quite lost on this question: Consider the example of a positive charge moving in the xy plane with velocity v = cos(theta)x + sin(theta)y (i.e., at angle theta with respect to the x axis). If the local magnetic field is in the +z direction, what is the...

I been trying to work out these problems for the past two days but cannot come up with a solution. If anyone can help that would be greatly appreciated. 1) A 3.80-g bullet moves with a speed of 180m/s perpendicular to the Earth’s magnetic field of 5.00 X 10-5 T. If the bullet possesses a net...

Which one has more magnetic field Torus or Bolt when current is going though? :eek:

Hey all smartie-pants! So this is the problem I have a tough time with: The magnetic field perpendicular to a single 13.2-cm-diameter circular loop of copper wire decreases uniformly from 0.750T to zero. If the wire is 2.25mm in diameter, how much charge moves past a point in the coil...

A 3.4g bullet moves with a speed of 160 m/s perpendicular to the Earth's magnetic field of 5x10^-5T. If the bullet possesses a net charge of 13.5 x 10^-9 C, by what distance will it be deflected from its path due to the Earth's magnetic field after it has traveled 1 km? I am confused. Do I...

I have tried everything to solve this problem, and I just cannot come to a conclusion. If anyone finds it comes easy to them, help will be greatly appreciated. :) Here goes: A straight stream of protons passes a given point in space at a rate of 1.5x10^9 protons/s. What magnetic field do...

A cyclotron designed to accelerate protons has an outer radius of 0.477 m. The protons are emitted nearly at rest from a source at the center and are accelerated through 610 V each time they cross the gap between the dees. The dees are between the poles of an electromagnet where the field is...

Hey, i have this question to solve.. An electron has a velocity of 1.62×104 m/s (in the positive x direction) and an acceleration of 2.25×1012 m/s2 (in the positive z direction) in uniform electric and magnetic fields. If the electric field has a magnitude of 19.1 N/C (in the positive z...

Consider the current loop in the figure below. Figure: http://east.ilrn.com/graphing/bca/user/appletImage?dbid=1450953670 Determine the magnetic field (in terms of a, I and d) at the origin. So I will use mu as the permeability of free space. Since the two vertical wires have opposite...

A very long straight wire carries current I. In the middle of the wire a right-angle bend is made. The bend forms an arc of a circle of radius r as shown in the figure below. Figure: http://east.ilrn.com/graphing/bca/user/appletImage?dbid=1161207397 Lets say the permeability of free space...

A metal rod having a mass per unit length p carries a current I. The rod hangs from two vertical wires in a uniform vertical magnetic field as shown in the figure below. The wires make an angle theta with the vertical when in equilibrium. Determine the magnitude of the magnetic field...

A 0.245-kg metal rod carrying a current of 10.5 A glides on two horizontal rails 0.480 m apart. What vertical magnetic field is required to keep the rod moving at a constant speed if the coefficient of kinetic friction between the rod and rails is 0.100? Again I am supposed to use the...

A conductor suspended by two flexible wires as in the figure below has a mass per unit length of 0.0800 kg/m. What current must exist in the conductor in order for the tension in the supporting wires to be zero when the magnetic field is 2.60 T into the page? Figure...

The rotor in a certain electric motor is a flat rectangular coil with 86 turns of wire and dimensions 2.60 cm by 3.80 cm. The rotor rotates in a uniform magnetic field of 0.950 T. When the plane of the rotor is perpendicular to the direction of the magnetic field, it carries a current of 7.3 mA...

Hello. :rolleyes: Do some materials have a magnetic field when electricity runs through them and they are in the superconductive state? Do they lose energy because of that field? Thank you. Miro

We all know that magnetic fields come from moving charge or electron spin. However if it were possible to have protons as a moving charge in a wire does that cause a B field? At first I thought that it obviously should but then I thought about how accelerating electrons emit EM waves...

Is the beauty and color to the Ring Nebula due to synchrotron radiation of particles (electrons) with higher energy (spin) being blueshifted the closer they are to the white dwarf at the center? If so is it the magnetic field that spins the electrons intensly and the futher away the electrons...

Hi, This is my first post on this forum. My question is How is motion of plasma controlled through magnetic fields since it is electrically neutral. My understanding is that since plasma conducts current, a current is passed through plasma and then a magnetic field is applied which...

I need help answering the following question: The energy of an electron in the p-level of an atom is changed in the presence of a magnetic field of magnatude 3.4T. What is the difference between the largest & smallest possible engergies? Thank you!

Magnetic Fields! I have to choose which of these are true false. And they are really confusing me. I know that the equation is F=qvB. However I am not sure what makes the problem different with constant velocity. Any help would be wonderful Consider a charged particle moving with a...

Can anyone help me with this? "A research lab has a magnetic facility, which can produce intense, pulsed magnetic fields. In 1 experiment, a B-field of 40 T is to be produced over a cylindrical volume, 40 cm in length and 20 cm in diameter. The energy required to pulse the magnet is...

I am so glad I found the link to this test, so I can reference questions with figures. let me write the problem first, and provide the link at the end, and in between explain where I was stuck. 87) two small pith balls, each carrying a charge q, are attached to the ends of a light rod of...

PART 1. Magnetic Field of Electron The electron and the proton both have Magnetic Moments. By definition (Penguin Dict. of Physics, 1991) the term Magnetic Moment means: 1. SYMBOL, m,: "A property possessed by a permanent magnet or current-carrying coil, used as a measure of the...