Magnetic field Definition and 1000 Threads

Homework Statement I have a rectangular coil with length L and the cross-section's sides has length a and b (b>a). A wire is tightly wrapped around N times. Calculate the magnetic field inside the coil. Homework Equations The problem I have is that in class we were taught how to calculate...

Homework Statement Each of two long straight parallel wires separated by a distance of 24.0 cm carries a current of 5.00 A in the same direction. What is the magnitude of the resulting magnetic field at a point that is 14.0 cm from each wire? Homework Equations U0I/2pir U0I/4pia(cos(theta)...

Homework Statement Lets say we have two horizontal rails connected by a resistor to the left, and we have a movable conducting rod that slides without friction on the rails.There is a uniform magnetic field going into the page. Homework Equations F = ILB[/B]The Attempt at a Solution Now, I...

Homework Statement A parallel plate capacitor of area 60cm^2 and separation 3mm is charged initially at 90 micro coulomb. If the medium between the plates get slightly conducting and the plate loses charge initially at the rate of 2.5 *10^-8 C per sec then what is the magnetic field between the...

Homework Statement A circle-formed circuit with an area A lies in the (xy)-plane. An electric current I runs clockwise through the circuit (figure 1). An external magnetic field B exerts a torque t = D(3i - 4j) on the circuit, where D is a positive constant, i is the x-axis unit vector and j is...

Homework Statement [/B] Magnetic field values are often determined by using a device known as a search coil. This technique depends on the measurement of the total charge passing through a coil in a time interval during which the magnetic flux linking the windings changes either because of the...

Magnetic field values are often determined by using a device known as a search coil. This technique depends on the measurement of the total charge passing through a coil in a time interval during which the magnetic flux linking the windings changes either because of the motion of the coil or...

Homework Statement A circular uniform laser beam has a power of P = 3.2 mW and a diameter of d = 8.5 mm. The beam is a form of electromagnetic raditation with both electric and magnetic field components. (a) Calculate the intensity of the beam in units of W/m^2 (b) Calculate the energy (delta...

I know that cathode rays follow a helical pattern if they enter a uniform magnetic field at an angle less than 90 degrees. This leaves me with two questions. 1. If the cathode ray described above, hit a phosphor coated screen, would it show only 1 spot or a circle? 2. If the magnetic field was...

(sorry my bad english) Let's imagine two frames of reference, one of which is a imaginary room containing two charges. Now let's accelerate this room from 0 to v and keep that speed during some time interval t and then we "pause" the situation again. An observer inside the box would measure the...

It is my understanding that fields store potential energy. That applies to both magnetic as well as electric fields. I know that the energy density also increases with the square of the norm of their vector value (at each coordinate). When I have an infinite current sheet, the math says[1] that...

Homework Statement An electron accelerated from rest through a voltage of 420 V enters a region of constant magnetic field. If the electron follows a circular path with a radius of 29 cm, what is the magnitude of the magnetic field? Homework Equations r=mv/lqlB K=VQ Conservation of Energy...

Homework Statement A negative charge q = −3.20×10-6C is located at the origin and has velocity υ⃗ =(7.50×104m/s)ι^+((−4.90)×104m/s)j^. At this instant what is the magnetic field produced by this charge at the point x = 0.230 m , y = -0.300 m , z= 0? Give the x, y and x components Homework...

1. The problem statemeent, all variables and given/known data The field electric's electromagnetic wave issued by a strut isotropic source is: \vec{E} = E_{0} r_{0}*cos(ωt − kr) \vec{θ} Find the magnetic field in spherical coordinates Homework Equations I think, i use the equation \vec{B} =...

Homework Statement The power cable for an electric trolley (see figure) carries a horizontal current of 330 A toward the east. The Earth's magnetic field has a strength 5.0 ✕ 10-5 T and makes an angle of dip of24° at this location. Calculate the magnitude and direction of the magnetic force on...

Homework Statement A dipole of moment ##\vec{p}## where p is fixed, moves with velocity ##\vec{v}## though a magnetic field ##\vec{B}##. Show that the force on the dipole is ##\vec{v}\times(\vec{p}\cdot\vec{\nabla})\vec{B}+\dot{\vec{p}}\times\vec{B}##. Homework Equations...

Hello! In this thread, in this answer, my statement "A time-varying electric field creates a magnetic field which is time-varying itself" was refuted. Because I never observed this before, I would like to discuss about it. As far as I know, Maxwell's equations are valid always together, that...

I have been unable to find a satisfactory explanation of this problem, elsewhere. Consider an uniform electric field, E, along the y axis. Consider also a uniform magnetic field, B, along the z axis. If we release a particle (charge=q, mass=m) at rest on the origin at time t=0, what will be...

Homework Statement Cyclotrons are widely used in nuclear medicine for producing short-lived radioactive isotopes. These cyclotrons typically accelerate H− (the hydrideion, which has one proton and two electrons) to an energy of 5MeV to 20MeV. This ion has a mass very close to that of a proton...

Homework Statement Hi, I know that this probably is easy to calculate, but I have the ability to thing the opposite about problems, therefore I'm stuck with this one. The question is Determine the number of times the magnetic field has wound around the Sun by a heliocentric distance of 70...

In addition, why is there no magnetic field along the line of motion of a charge? If length contraction occurs along this line of motion, I don't see why there is no magnetic field created along this line of motion for other charges to interact to. I get magnetism is fundamental, but at least...

Homework Statement A wire of mass 3.0g and length 60cm is placed on a table parallel to the East-West direction. If a current flows through the wire from West to East, how large must the current be to cause the wire to lift off the surface of the table? (The Earth's magnetic field has strength...

(Sorry my poor English) A changing electric field creates a magnetic field and vice-versa. I thought one field were created only when the another field were disturbed and it works finely for electromagnetic waves, and it agrees with Maxwell's equations. I was happy with my conclusion then I...

I have a set-up where there are multiple conductive wires separated by insulators placed parallel to one another and current ##I_w## is flowing within each conductor(all currents are parallel and equal),they create a magnetic field and I believe would add up like this diagram: The current is...

Hi. I'm currently learning about magnetism, however the course I'm in doesn't combine special relativity with E&M so I just wanted to do some personal exploring. The magnetic field for a point charge is proportional to V1 x R of the charge. Then, the magnetic force is proportional to V2 x B...

Homework Statement A proton moving with constant velocity enters a region containing a constant magnetic field that is directed along the z-axis at (x,y) = (0,0) as shown. The magnetic field extends for a distance D in the x-direction. The proton leaves the field having a velocity vector (Vx...

i am just a student who wishes to learn more about physics and the way the universe works, but because i am 14 and am just starting to learn all of this on my own i have to start from scratch, please present me with any usable information

Homework Statement We have seen that a long solenoid produces a uniform magnetic field directed along the axis of a cylindrical region. However, to produce a uniform magnetic field directed parallel to a diameter of a cylindrical region, one can use saddle coils. The loops are wrapped over a...

Homework Statement For a Stern-Gerlach experiment, there is a apparatus designed to create a magnetic gradient. There is a dipole magnet. The radius of the convex pole is 5 cm, the radius of the concave pole is 10 cm. The convex pole as a 2 T magnetic field along its surface. (The apparatus is...

Homework Statement A very long straight wire carries current I. In the middle of the wire a right-angle bbend is made. The bend forms an arc of a circle of radius r, as shown in the figure below. Determine the magnetic field at the center of the arc. Homework Equations Biot-Savart Law: ##dB...

So the electric and magnetic fields are linked, when they're at 90 degrees and self propagating they're a photon. I sort of know you can have TE and TM propagation. But I'm having trouble seeing how the electric field link is maintained with magnetism; can someone explain to me where the...

Lets say you have an electromagnet which produces some magnetic field when current is passed through it . Now there is some magnetic field in its surrounding then it is expected to exert some torque according to the formula torque=magnetic moment*magnetic field .Now my question is : will the...

Why only Earth has a magnetic field around it and not other planets?

Homework Statement Using the Logger Pro Program plot a graph with the angle on the horizontal axis and the measured field on the vertical axis. The curve should have its maximum value at (theta) = S . where cos( theta - S) = cos(0) = 1. Use your graph to determine S, the declination at your...

Homework Statement A charge q is released in crossed E and B fields: E is oriented along y axis; B is oriented about z axis Derive the equation of motion of q Homework EquationsThe Attempt at a Solution I'm not sure what equation I should use here, the only equation that I have which gives...

Hi guys!Im doing a Project about maxwell equations and need help with something. Let's say you have a current going through a copper wire with an insolation on, and ofcourse there is a magnetic field. I've wondering if the magnetic field have a temperatur impact on the cabelinsolation. I want...

For our physics class we have to design an experiment investigating the factors affecting an electromagnet's field strength. I have decided to investigate the number of coils in the wire. My only problem is, I'm not sure how to measure the field strength. Our teacher gave us two things which we...

Purcell has a paper in which he derives the magnetic field by assuming a charged particle travels alongside a conducting wire at the same velocity as the conduction electrons in the wire. The conduction electrons and the test charge are moving together but the positive charges are moving...

Hello, i've recently found the post "How to calculate the force acting on a magnet placed in a magnetic field?" at http://physics.stackexchange.com/questions/20258/how-to-calculate-the-force-acting-on-a-magnet-placed-in-a-magnetic-field in another Forum and the answer said smth about an...

Hi, I want to heat magnetic nanoparticles in an AC magnetic field. I need a uniform and a magnetic field about 15- 25 mT ) . I have thought about some designs, can you tell me which one is the most suitable design for creating a uniform alternating magnetic field? I need this system for...

Homework Statement Hey! I have trouble with an exercise that I need help with. Here it is: The magnetic field lines for the average interplanetary magnetic field (IMF) follow Archimedean spirals. i) Find the heliocentric distance r in Astronomical Units (AU), where a field line has wrapped...

If current I passes through a circular loop of radius R,then what will be the self inductance of that loop? (calculating flux through the loop leads to calculating magnetic field at every point inside the loop which is an elliptic integral.)

A magnetic field doesn't penetrate well into a plasma because it produces currents that counters the field, so to speak. But, before those currents are produced, does the whole of the plasma "feel" the magnetic field? For how long; ns, us or ms? S.A.

Apart from the orientation of a compass needle and the pattern formed by iron filings, what other proof do we have of magnetic field lines forming loops?

Hi, I'm developing a new bio reactor, which in this instance you can think of as just a perspex fish tank. But have come across an unusual requirement to apply a roughly 0.01T magnetic field across the volume of the tank with mainly water in it. No position in the tank can be less than 0.08T and...

Hey guys, So I have a bit of an interesting problem to solve here. I'm trying to calculate the upward repulsion force due to eddy currents created in a conductive surface by a rotating magnetic field. I'm doing this for an undergraduate lab project, and want to be able to provide quantifiable...

Magnetic field do no work. Is this always true? If so then what is the explanation of that crane thing?

I was just wondering if a beam of whatever charged particles can be compressed in velocity space if you send the beam through a (strong) magnetic field that is parallel to the beam? The charged particles (that are not moving exactly along the field lines) should spiral in the field in my opinion...

Can someone please explain to me why, a changing magnetic field can produce an electric field and a changing electrical field can produce a magnetic field. Also how do magnetic fields originate, what causes them?

Hello everyone I have a question: I know what alpha/omega dinamo is, and I think I have understood how this model explains Joy's law and Hale's law, but I don't get how it allows the magnetic field to become poloidal again (after having become toroidal due to differential rotation) and with the...