Magnetic field and forces Definition and 20 Threads

  1. Dex_

    Conversion factor when converting from SI to natural units

    For the right hand side I expressed each of the quantities in SI units, $$C \cdot \frac{kg}{A \cdot s^{2}} \cdot m$$ Then substitute newtons in as ##N = kg \cdot ms^{-2}## and we get, $$C \cdot \frac{N}{A \cdot m} \cdot m$$ Using the definition of work as ##J = N \cdot m## and Amperes as...
  2. C

    A NMR flip angle - angle of nutation

    Hi, I am interested in derivation of flip angle in nuclear magnetic resonance. We have magnetic dipole in static magnetic field. The magnetic dipole is precessing around the vector of this field with Larmore frequency. After applying square magnetic pulse with amplitude B1 oscillating on...
  3. A

    I Derivation of induced voltage in loop

    ##\phi_m = Blwcos\theta## voltage = ##\frac{-d\phi_m}{dt} = Blwsin\theta\frac{d\theta}{dt}## where l is the length of the loop and w is the width of the loop The top and bottom of the loop have magnetic forces perpendicular to the loop. My book says that means that there is no current through...
  4. J

    I Perfect conductor in rotating magnetic field

    Hello all, what would happen to a perfectly conducting cylinder immersed in a rotating magnetic field, with the rotation axis parallel to that of the cylinder? I guess the cylinder would start to rotate with the field? Right? Thank you
  5. Y0SHI0N

    Can two variables in two different equations cancel each other?

    Using the related equations, I have come up with an equation that I think would answer this question (#4). However, I was just wondering does the 'L' from equation #1 and 'l' in equation #3 cancels each other out when the substitution is made to give out equation #4 (since they are both the...
  6. Luke2642

    Force & energy in cutting and stretching magnetic field lines?

    I have an ordinary switchable magnet for holding tools to a lathe. It's like a magnetic force gearbox, but I can't quite understand the force multiplication. When placed on a steel surface the switch force is approximately ~5N on both finger and thumb at 1.5cm radius acting over a 3cm arc...
  7. Nonametheone

    Can Space-Time Differ for Ionized Fuel in a Magnetic Field Near Light Speed?

    Summary: Can a particle accelerator accelerate gaseous fuel? Does space-time differ for detonating ionized fuel moving near the speed of light within a magnetic field such as a particle accelerator?
  8. M

    Magnitude of the Magnetic Field near a Circuit Inclined at an Angle

    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...
  9. H

    What exactly is magnetism, anyway?

    After carefully reading textbooks, research papers and a lot of forums, I find myself more confused than ever regarding the composition of magnetic fields. So please let me ask some (hopefully) very simple questions: (1) Do we or do we not know exactly how magnetic fields arise and dissipate...
  10. M

    Magnetic field "lines" confused with magnetic field "vectors"

    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...
  11. R

    Derivation: force on magnetic moment in magnetic field

    I am trying to derive the equation ##\vec{\Gamma} = \vec{m} \times \vec{B}##, where ##\vec{m} = I \vec{A}## is the magnetic moment, and ##\vec{A}## is normal to surface ##A##, from the Lorentz force law ##\mathrm{d}\vec{F} = I \vec{dl} \times \vec{B}##. For an arbitrary closed current loop ##C##...
  12. G

    Magnetic Field from Protons vs Electrons

    If an electron is moving in a circle in a magnetic field, it produces a magnetic field in accordance to the right hand rule. If a proton is moving in a circle in a magnetic field, would it produce a magnetic field in accordance to the left hand equivalent to the right hand rule.
  13. H

    Find induced current, magnetic force, work in inclined plane

    Homework Statement [IMG]http://[url=https://ibb.co/b3Emfo]https://preview.ibb.co/gLaEY8/20180527_055248.jpg[ A conducting bar slides down without friction on a pair of conducting rails separated by distance d. Connected to resistor R and there magnetic field B directed upward, perpendicular to...
  14. H

    Electric Force on a Charge in a Solenoid

    Homework Statement [IMG]http://[url=https://ibb.co/dgUy6T]https://preview.ibb.co/iyqS0o/20180525_213806.jpg Since i only know the field direction, increasing go into page. Why the answer is C? Why the answer "a" ? The R and r on the pic is respected to what? Homework EquationsThe Attempt...
  15. M

    Charge moving with a constant linear velocity....

    Charge moving in constant linear velocity does not produce magnetic field... If not, please provide an explanation...
  16. abilolado

    I Force on Steel Bar Inside Solenoid

    Hello all. Me and some friends are building a coil cannon, and we've been doing some calculations [I know its unecessary but... well, we're physicists! (well, physics students...)]. But we got stuck. How to calculate the force acting on a steel bar (or some other ferromagnetic material, maybe...
  17. Astronaut

    Magnetic Forces on objects in nonuniform fields

    I have this question which I need to solve . But I am unable to. Suppose I have a current ring of radius R and current I (constant). at a distance x from the centre of the ring, I have a iron disk (radius r and thickness t) present in the plane of the ring. This disk will be attracted to the...
  18. M

    Physics 12: Acceleration of Proton in B-Field

    Homework Statement [/B] A proton is accelerated from rest at the positive plate of two charged parallel plates with a potential difference of 2000 v. After leaving the plates through a small hole in the negative plate, it enters a uniform magnetic field of 0.50 T in a direction perpendicular to...
  19. S

    Magnetic Fields- Finding the radius

    Homework Statement A single ionized uranium ion of mass 6.9 x 10 ^-25 kg is accelerated through a potential difference of 4.4 x 10^5 V. What is the radius of the path it would take if injected at 90 degrees into 0.47 T uniform magnetic field at this velocity? 3. Attempts Since centripetal...
  20. bob012345

    A How Do Nested Conducting Loops Interact Electromagnetically?

    Hello, As a heuristic tool for a complex problem, I'm trying to understand a series of nested conducting loops each with a initial identical current on it. These perfectly conducting loops are in the same plane each with that current in either direction. Each nested loop is perfectly...
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