1. C

    Plasma in a Solenoid

    ∇p=j×B (eq. 1) K=nI BSolenoid=μnI⇒μK (eq. 2) ∇p=-2p0r/(a2) (eq. 3) Combining these three equations: j=-2p0r/(a2μK) (θ hat direction) Feel like this is too simple and might be missing a step any help would be much appreciated!
  2. Kartoshka123

    Zeeman effect: Experimental Setup and Explanation

    Homework Statement: Hello, I have to explain using numbers the Zeeman effect for hydrogen and the setup needed. I have done some research and if I'm not wrong, then a magnetic field of 1 Tesla is needed. I have no idea how to achieve that using commercially available products and how to even...
  3. T

    Inductance of a Solenoid with a Core inside

    For finding magnetic field ##B##, We see this question like two Solenoids. for the first one, we have ##\int B ds = \mu I## so ##B x_0 = \mu I n x_0 ## so ##B = \mu n I##. For the second one we have ##B = \mu_0 n I##. For the Inductance we have ##L = \mu l n^2 A## so we have ##L_1 = \mu x_0...
  4. K

    Strength of magnetic field at the end of a wire wrapped nail.

    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...
  5. B

    I Biot Savart Law with Different Magnetic Permeabilities

    I would like to make a program that produces a 2D heat map showing the magnitude of the magnetic field produced by a finite length solenoid. The heat map would show the field strength along the radial and axial directions of the solenoid. I plan to divide the conductor into "infinitessimally"...
  6. marino

    Power generated by a coil rotating in magnetic field

    The problem: a coil of radius r, length l and N turns, rotating with constant angular velocity ω around an axis perpendicular to its simmetric axis and passing for the center of the coil. The coils is submersed in a static magnetic field, intensity B0, perpendicular to the axis of rotation of...
  7. Limddong

    I Magnetic field inside a solenoid calculated with Ampere's law

    I think the real magenetic field is sum of the magnetic fields calculated in each cross section of solenoid with various angle and same center axis when i apply Ampere's law. (Imagine the cross section contains a part of center line of the solenoid) Please let me know why we don't do like that. :)
  8. D

    Ratio of Inductance between 2 Solenoids?

    1. Homework Statement 1. Two solenoids, A and B, are wound using equal lengths of the same kind of wire. The length of the axis of each solenoid is large compared with its diameter. The axial length of A is twice as large as that of B, and A has twice as many turns as B. What is the ratio...
  9. shahbaznihal

    I Total magnetic flux of a solenoid

    There is a solenoid of a certain radius, carrying a certain current. I draw an amperian loop of radius greater than the radius of the solenoid. If I calculate the total flux through this loop it should be, 1) Non zero for an ideal solenoid (where the field outside the core of the solenoid is...
  10. F

    EMF induced in a coil encircling an ideal solenoid

    1. Homework Statement A current I(t)= (0,160 A s^{-3}) t^3 flows through an ideal solenoid with a turns density n = 9,00 \cdot 10^{-3} m^{-1} and a cross sectional area A_s=2,00\cdot 10^{-4} m^2 A single loop of wire has the same axis as the solenoid, but its radius is larger. That is: the...
  11. Alettix

    Magnetic field decay in cylinder coaxial with solenoid

    1. Homework Statement For a medium of conductivity ##\sigma##: $$ \nabla^2 \vec{B} = \sigma \mu \mu_0 \frac{\partial \vec{B}}{\partial t} + \mu \mu_0 \epsilon \epsilon_0 \frac{\partial^2 \vec{B}}{\partial^2 t} $$ A long solenoid with ##r=b## has n turns per unit length of superconducting wire...
  12. Ron Burgundypants

    I Altered inductance around a solenoid in a cryostat (from Eddy currents?)

    I'm trying to use a solenoid to measure the magnetocaloric effect of dysprosium. The effect is highest at the Neel temp which is down near 180K. I have a solenoid in a cryostat to get the correct temperature. The cryostat's heat exchanger is made of a thick copper cylinder and I think it is...
  13. B

    B Homemade electromagnet, considerations - strength

    I'm making a solenoid electromagnet for gcse demonstration purposes and I'm trying to get a strong:muscle:, clear magnetic effect. I'v wrapped about 100 turns of enamel plated copper wire around a 4" bolt and also a 4" ferrite rod, and am applying 9v DC from a pp3 battery cell. In both cases...
  14. C

    Induced EMF in a coil outside a solenoid

    1. Homework Statement A conducting coil of radius R is outside a long solenoid with a cross section of radius r. What is the emf induced in the coil? Most example problems of this type I think are solved based on Faraday’s Law. These examples do not use the distance from the solenoid to the...
  15. Toby_phys

    Energy of a solenoid with a partially removed core

    1. Homework Statement A solenoid of volume V, current I and n turns per unit length has an LIH core, relative permitivity is \mu_r. This core is then slid out so that a fraction f of the solenoid's length is filled with air/vacuum (and 1-f is filled with the core). Neglecting hysteresis...
  16. R

    I Magnetic field and Poynting Flux in an Inductor

    Hi everyone, Lately I have been studying the Poynting Flux and I am familiar with the classic examples of how it can be used to describe the power being dissipated by a resistor and the energy flowing into a capacitor, but I have never come across a similar analog for how the Poynting flux...
  17. F

    B What's the relationship between drop height and induced emf?

    In my experiment, I intended to find out how the change in the bar magnet drop height from solenoid affected the emf induced in the solenoid, however, I am unable to come up with an equation that shows a relationship between the two variables. I have thought of Biot-Savart law, but I do not...
  18. M

    Solenoid with current carrying wire inside

    1. Homework Statement I have a solenoid with a wire carrying current in the center. The wire has a radius of a, the solenoid has a radius of b. I need to find the magnetic field inside of each region. Inside of the wire, mu =/= muo. 2. Homework Equations Wire B field = uo I/2*pi*r Solenoid B...
  19. A

    Actuating Pencil To Draw Waveforms

    I am looking to make a pencil whose tip moves to create a waveform as you move it across the paper.In essence, I want to be able to record a sound and then play the sound through the pencil whilst I draw with it, of course, I will use software to lower the frequency to make it more of a waveform...
  20. C

    B How will the magnetic field change if I rotate the solenoid?

    If I do the x axis rotation for a solenoid, how will the magnetic field change? Would it also rotate along x axis?
  21. 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...
  22. S

    Solenoid (magnetising current)

    1. Homework Statement Part d of attached question 2. Homework Equations Solenoid equations B=uo n i 3. The Attempt at a Solution B (absence)=B (presence) Uo n (i+im)=u n i im=798A But answer is 794A.
  23. M

    Two solenoids in parallel

    Hi - I am designing a circuit with two solenoids (12 V, 1 Amp each) in parallel in order to get power of two upon activation using an arduino. I am able to wire one solenoid using 12 V adapter rated 3 Amp, 1 TIP120 darlington transistor, 1N004 diode and Arduino connected to base of the...
  24. sean1832725142

    I Magnetic Energy of solenoid( u=m·B or u=B^2/4pi )

    Hi, I have a problem with the fomular u=m·B and u=B^2/4pi Since I want to calculate how many magnetic energy on a solenoid, I couldn't decide which fomular should I use.
  25. Asmaa Mohammad

    Calculating the number of turns of a solenoid.

    1. Homework Statement 2. Homework Equations B = μ Ni/l 3. The Attempt at a Solution Question no. a: And Q no. b: I am not sure about the step in the red circle in the first figure, and my book doesn't give a solution, so what is your opinion?
  26. C

    Need help doing force calculations with magnetism (between magnets)

    I am trying to calculate the forces (in Newtons) between a permanent magnet, and an electromagnet. All I can find is interactions between permanent magnets, electromagnets, but never both and it is getting really confusing for me to do the calculations. So basically, if I have a permanent...
  27. G

    Homopolar generator: disk vs. helix

    Hi, I'd like to build a homopolar generator. Since generating magnetic fields of uniform density of any useful size is very tricky to do with off the shelf permanent magnets (I've tried!) I had the idea to use DC solenoids instead. But with a rotating helical plate in place of the cylindrical...
  28. r_prieto5

    Solenoid force calculation

    Hello everyone, So for a personal project I want to calculate the force necessary for a solenoid (electromagnetic coil) to keep a permanent magnet triangle locked diagonally up and down at the same time so that it does not move in any direction. I need to know the values for coil thickness...
  29. T

    I Force generated by a solenoid on a moving steel ball bearing

    Hi, I want to find an equation for the force generated by a solenoid on a moving steel ball bearing given current, number of loops, area of the solenoid for a lab project. I've tried looking through many sources, but was unable to find anything. I also tried looking at this previous discussion...