What is Magnetic force: Definition and 413 Discussions

In physics (specifically in electromagnetism) the Lorentz force (or electromagnetic force) is the combination of electric and magnetic force on a point charge due to electromagnetic fields. A particle of charge q moving with a velocity v in an electric field E and a magnetic field B experiences a force of





F

=
q


E

+
q


v

×

B



{\displaystyle \mathbf {F} =q\,\mathbf {E} +q\,\mathbf {v} \times \mathbf {B} }
(in SI units). It says that the electromagnetic force on a charge q is a combination of a force in the direction of the electric field E proportional to the magnitude of the field and the quantity of charge, and a force at right angles to the magnetic field B and the velocity v of the charge, proportional to the magnitude of the field, the charge, and the velocity. Variations on this basic formula describe the magnetic force on a current-carrying wire (sometimes called Laplace force), the electromotive force in a wire loop moving through a magnetic field (an aspect of Faraday's law of induction), and the force on a moving charged particle.
Historians suggest that the law is implicit in a paper by James Clerk Maxwell, published in 1865. Hendrik Lorentz arrived at a complete derivation in 1895, identifying the contribution of the electric force a few years after Oliver Heaviside correctly identified the contribution of the magnetic force.

View More On Wikipedia.org
  1. S

    How Does Magnetic Force Affect a Wire in a Field?

    Homework Statement A wire is oriented along the x-axis. It is connected to two batteries, and a conventional current of 2.3 A runs through the wire, in the +x direction. Along 0.27 m of the length of the wire there is a magnetic field of 0.82 tesla in the +y direction, due to a large magnet...
  2. B

    The true speed of Electric and Magnetic force.

    To all the experts: Ok, in this example, I'm going to have an "ideal" circuit with no ohmic losses, etc. just for ease of calculation... The circuit is connected to a power source with it's own on/off switch. I turn on the power source and... 1. How fast does the Electric Force...
  3. K

    Magnetic Force of a copper wire

    Homework Statement The top wire is 1.00 mm diameter copper wire and is suspended in air due to the two magnetic forces from the bottom two wires. The current flow through the two bottom wires is 95 A in each. Calculate the required current flow in the suspended wire. Homework...
  4. C

    Net magnetic force on a loop parallel to a wire

    Homework Statement A long, straight wire carries a current of I1 = 15.8 A. Next to the wire is a square loop with sides L = 1.17 m in length. d = 1.42 m, as shown in the figure below. The loop carries a current of I2 = 2.66 A in a direction parallel to the wire. Calculate the magnitude of...
  5. H

    Can I calculate magnetic force of a magnet?

    Is there a way of calculating how much force can be applied to an object if you are given the magnetic field strength of an electromagnetic? For example, if an electromagnet produces a B field of 4T, what is the maximum mass of iron it can hold? And also, how does one calculate the...
  6. K

    What is the Magnitude of Magnetic Force on an Electron in Various Orientations?

    Homework Statement An electron travels at a speed of 2.0x10^4 m/s through a uniform magnetic field whose magnitude is 1.2x10^-3 T. What is the magnitude of the magnetic force on an electron if its velocity and magnetic field: a. are perpendicular? b. make an angle of 45 degrees? c. are...
  7. M

    Charge Acted By Magnetic Force AND Friction

    Homework Statement Part 1: A charge particle having charge q enters a region in which there is a friction force proportional to the speed of the particle. The constant of proportionality of friction is "b". The particle stops traveling a distance of 10m, in a straight line. Now, the experiment...
  8. M

    How can Gauss value be used to calculate magnetic force in Newtons?

    Hi, I'm buying magnets for a required experiment in my magnetic and electricity physics class. The supplier gives to important pieces of information: BrMax: 3850 gauss and Pull Force: 33lbs. I was wondering if there is a relatively simple formula so that I can calculate the force of the magnet...
  9. S

    Magnetic force would it take to launch 1,000 , 5,000 and 10,000 pounds

    how much magnetic force would it take to launch 1,000 , 5,000 and 10,000 pounds into orbit? of say 270 miles up, using an electromagnet. also how much energy would be required to produce this force and lastly how much energy can be gotten from a dam(hydroelectric power plant) and how much...
  10. A

    Magnetic Force on Moving Charges

    A proton high above the equator approaches the Earth moving straight downward with a speed of 355 m/s. Find the acceleration of the proton, given that the magnetic field at its altitude is 4.05 X 10^-5 T. Homework Equations F = MA =eVBsin? a = evB/m The Attempt at a Solution...
  11. KleZMeR

    How Does a Rectangular Loop in a Magnetic Field Behave?

    Homework Statement There is a rectangular loop submerged in uniform magnetic field, where all but one edge is in the field, and I am given W (length), Bo, R (resistance), L (self-inductance), m. I am to find v(t), y(t), and i(t). when R = 0 and L =/ 0 (L is NOT =0) Homework...
  12. S

    Magnetic force on a wire problem

    Homework Statement A packed bundle of 100 long, straight, insulated wires forms a cylinder of radius R = 0.500 cm. (a) If each wire carries 2.00 A, what are the magnitude and direction of the magnetic force per unit length acting on a wire located 0.200 cm from the center of the bundle?Homework...
  13. M

    Net magnetic force in unit-vector notation

    Homework Statement The bent wire shown in the figure below lies in a uniform magnetic field. Each straight section is 2.0 m long and makes an angle of θ = 65° with the x axis, and the wire carries a current of 2.0 A. (a) What is the net magnetic force on the wire in unit-vector notation if...
  14. B

    Magnetic force on wires -direction of B

    Homework Statement Three wires have linear density of 50 g/m. They each carry the same current. The bottom two are 4 cm apart and carry currents into the page. What current I will allow the third wire to float so as to form an equilateral triangle with the other two? Homework Equations...
  15. B

    Magnetic force question - should be easy

    Homework Statement 1) An electron moves in a magnetic field B = .50 i with a speed of 1.0 x 10^7 m/s 45 degrees above the positive y axis. What is the magnetic force on the electron? Homework Equations The Attempt at a Solution 1)This should be an easy question, but I am...
  16. I

    Magnetic Force Per Unit Length

    Homework Statement A packed bundle of 100 long, straight, insulated wires forms a cylinder of radius R = 0.600 cm. If each wire carries 4.50 A, what are the magnitude and direction of the magnetic force per unit length acting on a wire located 0.200 cm from the center of the bundle?Homework...
  17. G

    Magnetic Force on a Moving Charge

    Homework Statement A magnet produces a 0.5 T field between its poles, directed to the east. A dust particle with charge q = -8 times 10-18 C is moving straight down at 0.6 cm/s in this field. What is the magnitude and direction of the magnetic force on the dust particle? Homework...
  18. S

    What Happens to a Proton in a Magnetic Field?

    Homework Statement A proton with the speed 3.7*10^6 m/s is moving in a magnetic field, parallel to the field. The magnetic B-force is 0.45T. a)Draw a figure that shows the proton in the magnetic field. Indicate the direction of the proton's velocity, the direction of the magnetic field and...
  19. S

    How powerful should the magnet be to repel against gravity?

    i have two magnets and i want to repel one magnet against gravitational force upwards..so how powerful the magnet should be?i can calculate the gravitational force using Newton's law f=gm1m2/r2 where m1 is mass of Earth and m2 is mass of one magnet...so the magnetic force should be greater than...
  20. T

    Calculating Charge Ratio in a Uniform Magnetic Field

    magnetic force help ? Homework Statement Two charged particles move in the same direction with respect to the same magnetic field. Particle 1 travels eight times faster than particle 2. However, each particle experiences a magnetic force of the same magnitude. Find the ratio q1/q2 of the...
  21. K

    What is the Maximum Magnetic Force on an Electron in a Television Set?

    Homework Statement In a television set, electrons are accelerated from rest through a potential difference of 23 kV. The electrons then pass through a 0.29 T magnetic field that deflects them to the appropriate spot on the screen. Find the magnitude of the maximum magnetic force that an...
  22. T

    Calculating Maximum Magnetic Force on Electrons in a Television Set

    magnetic force help ? Homework Statement In a television set, electrons are accelerated from rest through a potential difference of 23 kV. The electrons then pass through a 0.27 T magnetic field that deflects them to the appropriate spot on the screen. Find the magnitude of the maximum...
  23. S

    Magnetic force, finding angle between velocity and magnetic field

    Homework Statement a 3 microcoulomb charge having a speed of 10m/s is fired into a region of constant magnetic field where B is given by: B = 0.3i - 0.4j a) the magnitude force on the charge is found to be 2*10^-6 Newtons. what is the angle between v and B? b) if the direction of v is...
  24. S

    Current on wire, three axes, magnetic force

    Homework Statement a 0.2 meter straight piece of wire has a current of 30 ampere flowing through it, pointing in the +z direction. the magnetic field presented in space is given by: B = 2B_0i + 4B_0j + 3B_0k what is the force on the wire? Homework Equations magnetic force on a...
  25. S

    Magnetic force between conductors

    Homework Statement a straight conductor carrying 5A is separated by 10cm from a second parallel conductor carrying 10A in the same direction. at what distance from the first conductor (along the line connecting the two conductors) is the magnetic field zero? Homework Equations F_2 =...
  26. T

    How Much Is a Charged Bullet Deflected by Earth's Magnetic Field?

    A 3.10 bullet moves with a speed of 165 m/s perpendicular to the Earth's magnetic field of 5.00x10^-5. If the bullet possesses a net charge of 1.36×10−8C , by what distance will it be deflected from its path due to the Earth's magnetic field after it has traveled 1.35km ? Could anyone...
  27. G

    Radius of Circular Path Affected by Magnetic Force: Increase or Decrease?

    Homework Statement An electron moves in a circular path in a vacuum under the influence of a magnetic field perpendicular to and into the paper.If there is another electron which moves with a higher speed in a circular path in the same B-field, state and explain how each of the following will...
  28. A

    Involves magnetic force and point charges with constant velocity.

    A point charge is moving at 1 x 10^6 meters per second. At the origin (0,0), a magnetic field of 1 T is applied into the page. The charge = 1.6 x 10^/10 C. 1) Calculate the force. 2) Calculate the exact location it hits the X intercept. 3) Calculate the time is takes to hit the X intercept...
  29. R

    How Do You Calculate Magnetic Force in a Moving Conductor Setup?

    I have a problem where I'm given a conducting bar that slides to the right on 2 conducting rails. The magnetic field is given, as well as the resistance, the length of the bar, and the speed that the bar is moving. The magnetic force is what is wanted. Now I know 3 formulas F= qv x B, F...
  30. Q

    Is the Magnetic Force Really Doing No Work?

    Anyone who has studied electromagnetism knows that the magnetic force on a moving electrically charged particle such as an electron in a magnetic field is always perpendicular to its direction of motion. Since the magnetic force on it is perpendicular to its motion, no work is done on the...
  31. rocomath

    Magnetic Force, simple length question

    Univ. Physics Young & Freedman, 12th edition (I am not at home right now, so if you have the book, refer to the picture!) - Ch. 27 #62 A long, straight wire containing a semicircular region of radius .95m is placed in a uniform magnetic field of magnitude 2.2T and length 3m. What is the net...
  32. A

    Magnetic Force on a Wire with a Changing Direction of Current

    Homework Statement A segment of wire carries a current of 62 A along the x-axis from x=-6m to x=0 and then along the z-axis from z=0 to z=2.9m. The magnetic field is equal to 110 mT in the positive z direction. What is the magnitude of the force on this segment of wire? Answer in units of...
  33. E

    Magnetic Force of Attraction Between Spinning Charged Shells

    Homework Statement Calculate the magnetic force of attraction between the northern and southern hemispheres of a spinning charged spherical shell. (ex. 5.11) Homework Equations The Attempt at a Solution I already looked at this https://www.physicsforums.com/showthread.php?t=42020. I am stuck...
  34. Q

    Copper wire magnetic force help

    Question Details: In the figure the top wire is 1.1 -diameter copper wire and is suspended in air due to the two magnetic forces from the bottom two wires. The current is 50 in each of the two bottom wires. Calculate the required current flow in the suspended wire. i have been working...
  35. G

    Magnetic Force: Causes & Effects of Opposite Poles

    What causes the magnetic force between 2 magnetic poles?
  36. N

    Magnetic Force on Charged Particle: True or False?

    Homework Statement A charged particle is moving in a uniform magnetic field. Which of the following statements concerning the magnetic force exerted on the particle is false? A) It increases the speed of the particle. B) It does no work on the particle. C) It changes the velocity of...
  37. S

    Solving a Magnetic Force Problem: Finding q & r

    Problem: A positively charged particle of mass 7.21×10-8kg is traveling due east with a speed of 89.9m/s and enters a 0.290T uniform magnetic field. The particle moves through one-quarter of a circle in a time of 2.06×10-3s, at which time it leaves the field heading due south. All during the...
  38. G

    How does a magnetic crane lift a car if the magnetic force doesn't do any work?

    My professor brought this up in class the other day, but has yet to elaborate on it and i can't stop thinking about it. I don't know if my wording is correct either so correct me if I'm wrong: The magnetic force will always act perpendicular to the displacement of a particle. Therefore, the...
  39. A

    Magnetic force between two parallel moving charges

    Hi everyone, I have been trying to find an answer to the following question on several websites on the topic, but no luck until so far. Maybe there is someone who can help me here: question: If two charges move parallel to each other (say in vacuum and relative to me), with equal speed...
  40. Y

    Photons associated with magnetic force

    Hi guys First of all apologies if my question appears naive or simplistic - new to this field. I have read that the force carrier for the electromagnetic force is the photon. So I bring the same poles of two magnets together and feel the repulsive force thus produced. I am unaware of any...
  41. A

    Magnetic Force on a Charged Particle in Constant Magnetic Field

    Homework Statement A charged particle is moving in a uniform, constant magnetic field. Which one of the following statements concerning the magnetic force exerted on the particle is false? It changes the velocity of the particle. It increases the speed of the particle. It does not...
  42. T

    Magnetic force on a charge carrying wire

    [SOLVED] Magnetic force on a charge carrying wire Homework Statement A current carrying wire is in a magnetic field as shown below. The magnet is on a scale. Given this setup, does the scale read more or less weight? Explain using the Right Hand Rule and Newton's Third Law. Note: The...
  43. B

    Calculating Angle for Magnetic Force of 2.2F

    When a charged particle moves at an angle of 19° with respect to a magnetic field, it experiences a magnetic force of magnitude F. At what angle (less than 90°) with respect to this field will this particle, moving at the same speed, experience a magnetic force of magnitude 2.2F?
  44. B

    Calculating Maximum Magnetic Force on an Electron in a Television Set

    In a television set, electrons are accelerated from rest through a potential difference of 23 kV. The electrons then pass through a 0.28 T magnetic field that deflects them to the appropriate spot on the screen. Find the magnitude of the maximum magnetic force that an electron can experience...
  45. J

    Investigating the effect of magnetic force on a current carrying wire

    [SOLVED] investigating the effect of magnetic force on a current carrying wire Homework Statement The aim of this experiment is to investigate the magnetic force of a current-carrying wire. In this experiment we will investigate the effect of current and to do this one shall measure the force...
  46. K

    How Fast Must You Drive to Experience a 210N Magnetic Force on Your Head?

    Homework Statement Oops, I forgot to add in the second part of the problem. Here's the original question plus the second part of the question. The strength of Earth's magnetic field at the equator is approximately equal to 5e-5 Tesla. The force on a charge q moving in a direction...
  47. K

    How Does Earth's Magnetic Field Affect a Charged Object in Motion?

    Homework Statement The strength of Earth's magnetic field at the equator is approximately equal to 5e-5 Tesla. The force on a charge q moving in a direction perpendicular to a magnetic field is given by F = qvB, where v is the speed of the particle. The direction of the force is given by the...
  48. K

    How Is Magnetic Force Calculated on an Electron in a Uniform Field?

    Homework Statement An electron in a vacuum is first accelerated by a voltage of 48200 V and then enters a region in which there is a uniform magnetic field of 0.183 T at right angles to the direction of the electron's motion. What is the force on the electron due to the magnetic field...
  49. F

    Magnetic force with spring and resistor problem

    I am having a great deal of trouble solving the following problem. Can anyone help? A straight wire of mass 10.2 g and length 5.0 cm is suspended from two identical springs that, in turn, form a closed circuit (Fig. P19.66). The springs stretch a distance of 0.51 cm under the weight of the...
  50. F

    Solve for Magnetic Force with Unequal Length Wires | Quick Question

    Homework Statement Quick Question, you know that if two wires are 1 metre apart, both are 10 m long, they both carry 1 A, and the magnetic field they are in is 5 T, you would do the following to solve for force: F=(4pi x10^-7)(1A)(1A)(10m)/2pi*1 But what if the two wires are different...
Back
Top