1. ### I 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...
2. ### Number of Turns vs. Wire Gauge (BLDC Motor)

Summary: For the same mass of copper wire, would more turns or greater thickness create a stronger magnetic field from a coil? So I am attempting to make a brush less DC motor, and I am wondering whether the coils would create a greater magnetic force if there are more turns or if the wire is...
3. ### Imperfections in magnet pole pieces

Hi all, I'm fairly new here. I'm currently designing an as-homogene-as-possible permanent magnet for low-field NMR and similar experiments. I'm on a fairly tight budget, and having finally found pole pieces for my magnets, I got them even though they have a small saw cut in the edge. approx. 5...
4. M

### I Electromagnet that can generate 100 lbs at small size

I wondering if it is possible to create an electromagnet that has a diameter of 0.5 cm that can generate 75 - 100 lbs of pull force. I took physics in college so I have a basic understanding of how magnets work, but I don't have any practical knowledge. I don't know what is feasible. I found...
5. ### B If a magnet could switch, could it attract and repel?

Hello the first image with the letters going ABCD is picture #1 and then BACD is picture #2 for references. Tools: - Normal magnet. Nothing special about them. - And we will say they have some type of system where they do not move sideways. Only up and down and have a difference of 5 cm when...
6. ### B Small size Motor to generate this torque

Good day everyone. I have two magnets where if I rotate them 20° they disconnect. It has a 0.4 N* m force of torque. I want to make them move with a motor. However I need it as little as possible. So after doing research I found tiny motors that are around 4000 RPM. It doesn't mention the HP...
7. ### B Repulsion of the Earth's Magnetic Field

I have a question why a magnet's magnetic field or a coil's magnetic field will not oppose the Earth's magnetic field? Is it because the earth's field is not strong enough or the magnet/coil doesn't cover enough square area? What formula's would I use to figure out what strength or area I...
8. ### B Magnetism Question

My 7 year old child asked me today about magnetism. His question was "Does the magnet pull in the paper clip, or does the paper clip pull the magnet" . He then said to me "If i tie a rope to a tree and pull on the rope with enough force I will be dragged to the tree, so how do you know which...
9. ### I What causes magnetism at the atomic level?

Lets assume we have a 1 foot square bar of Iron. I realize that unpaired valence shell electrons in an atom of a substance like Iron, all with the same electron spin---either +1/2 or -1/2---are consistent within the same atom, as indicated from the aufbau principle and experiments. So for an...
10. ### I Creating any shape of a magnetic field?

I was wondering if it was possible to create any shape of magnetic field. If yes, what would it take to do so?
11. ### B In layman's terms , how strong is a 3 Tesla Magnet?

I saw a post where someone was granted access to a 1.5 Tesla MRI. After some research I discovered a 3 Tesla MRI. How strong is this magnet?
12. ### I Suspend a magnet on a pendulum above a repelling magnet

Hi, I was pondering a question after seeing a video about chaotic magnetic pendulums. If you were to suspend a magnet on a pendulum above a repelling magnet, would it stop moving or would you get perpetual motion? My guess is it would stop moving but I cant think of how. Gravity would try to...
13. ### Electromagnetism homework check

Hello. I have an assignment to submit and I really want to get full marks/know where I went wrong If anyone has a tiny bit of free time would you mind please checking my homework? Even if you just check 1 page I will be so grateful. Thanks again https://imgur.com/a/rHVdjzn
14. ### B 4 Questions About Lenz's Law Experiment

Hello, I have four questions. As it stands now, I don't have the necessary materials to test this myself, which is how I'd prefer to learn the answer. I still plan on doing this experiment for fun once I can acquire the necessary components. This deals with Lenz's Law. My goal is to maximize...
15. ### Force on conductor in magnetic field

Homework Statement Homework Equations Emf=B l V V is (velocity) F=QVB The Attempt at a Solution Emf=BLV Work=QBLV Force=BLV how come V=Q/m. its not possible or is it?
16. ### Calculating flux with a magnet and a coil

Homework Statement [/B] Hey, I'm having some difficulties with my physics project and I hoped someone could help me out. We have to calculate the magnetic field, but first we need to know the flux. This is the setup we got: We have to let a magnet fall through a PVC tube. The tube has a coil...
17. ### I Is it possible to create a magnetic field which can be seen?

Hello, I am wondering if one can create a magnetic field which can be seen by a human eye? I have learnt that light is nothing else but electromagnetic field with a wavelength between 400-800 nm. Colours correspond to different wavelength within the above spectrum. So isn't it theoretically...
18. ### I How to test toroidal permanent magnet with inside field

As the permanent magnet is magnetized by donut shape coil, thus field B = 0 outside. How can I know if seller screwed me or not?
19. ### Speed of a Magnet Falling through a Conducting Wire

Homework Statement A small but very powerful bar magnet falls from rest under gravity through the center of a horizontal ring of conducting wire, as shown in the figure below (on the left). The speed-versus-time graph, in arbitrary units, of the magnet will correspond most closely to which of...
20. ### I Need references for magnetic force vs distance/angle topic

Hi, i'm finishing my final degree project, it's about a new type of pallet conveyor dragged by magnets. I know for a fact that magentic force is inversely proportional to the distance squared, and i've designed and built my prototype with that in mind. Now i'm writing my final report and i need...
21. ### B Magnetic Field of an AA Battery 'Immersed' in a Conductor

If an AA battery were placed in some kind of ideal conducting 'ether': 1) Would current flow, and if so, what would the flow of electrons look like? 2) How would the magnetic field look? (I imagine that if there was an electric current flowing, that the magnetic field would look a little like...
22. ### I Cutting magnets

Hello, could someone explain to me, how I should cut a FeBa magnet, if it has one pole facing upward and the other downward so that the bloch wall would be across the entire length of the magnet. The dimensions of the magnet at hand are 152 x 102 x 52 mm. The bloch wall runs across the entire...
23. U

### How rubbing a needle on a magnet affects its polarity

Homework Statement It is known that when rubbing a needle on a magnet, the needle will become magnetized. If you rub the needle on the north side of the magnet, will it point differently than if you rubbed it on the south side of the magnet? Does it matter what direction you rub the needle...
24. K

### Inducing electricity w/ moving piece of metal, static magnet

Hi! I'm curious to know, whether it is possible to produce electricity by moving a piece of metal over a magnet (i.e a immobile magnet and a moving piece of metal close to the magnet), and how this would be done in practice.
25. ### A Obtaining position in a dipole field

Hi all, Consider one has a magnetic dipole, the field given by: \begin{equation} \vec{B} = \frac{\mu_0}{4\pi}\left(\frac{3(\vec{m}\cdot\vec{r})\vec{r}}{r^5}-\frac{\vec{m}}{r^3}\right) \end{equation} where we can take $$\vec{m} = m\hat{y}$$. Let us say we have the a magnet vector which is...
26. S

### Moving charges and magnetism

Homework Statement current in wire is in east to west direction.direction of magneetic field below the line Homework Equations right hand thumb rule The Attempt at a Solution i used the right hand thumb rule to find the direction of magnetic field but the magnetic field comes out in in the...
27. S

### I Where does the formula I = -e/T comes from?

Yeah, where does it comes from?
28. ### MOSFET or Rheostat or Potentiometer pros and cons?

Preface: I'm a chemical engineering undergraduate student but as small-time and noob electrical engineering hobbyist. I really only have minimal experience in circuitry and the like. I want to build a series of electromagnets with a variable their strength in order to levitate an opposing...
29. ### How can the neutral outer core generate a magnetic field?

Even if the outer core is convecting and conductive it is still charge neutral, so how can a Magnetic field be generated? Maxwells Equation say there needs to be net charge moving for a Magnetic field to be generated.
30. ### 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...