# solenoid

1. ### 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. ### 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...

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13. ### 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...
14. ### 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...
15. ### 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...
16. ### 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...
17. ### 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...
18. ### 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...
19. ### 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...
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### 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...
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### 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?
22. ### 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...
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### 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.
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### 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...
25. ### 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.
26. ### 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?
27. ### 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...
28. ### 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...
29. ### 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...
30. ### 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...