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........The proof was achieved by using radial or circular concentric slits instead of a solid copper disc. The eddy currents are prevented from spreading through these slits; thus the associated magnetic field can no longer attain the strength of a solid disc. Consequently, the magnetic needle remains almost at rest.
Quote........The proof was achieved by using radial or circular concentric slits instead of a solid copper disc. The eddy currents are prevented from spreading through these slits; thus the associated magnetic field can no longer attain the strength of a solid disc. Consequently, the magnetic needle remains almost at rest.Thus proving that it is not an electrostatic effect. Very clever!
radial current = flow of charge.
I couldn't find a specific experiment video that directly demonstrates the generation of a magnetic field by spinning an electrically charged disk, based on available information and the provided search results. However, I can explain why such a video might be rare, describe the theoretical basis for the experiment, and point you toward related resources or experiments that come close. I'll also address the context of your previous questions about planetary precession and angular momentum to ensure the response is cohesive......Why Specific Videos Are Hard to FindExperimental Challenges:Small Magnetic Field: Even with a highly charged disk (e.g., 20 pF at 10 kV, yielding 2 μC) spinning at 100 Hz, the resulting current is small (~0.2 mA), producing a weak magnetic field that requires sensitive detectors.Charge Retention: Maintaining a stable charge on a rapidly spinning disk is difficult due to leakage or discharge, especially in air. Vacuum setups or specialized materials are needed.Practicality: The experiment is less common in educational settings because simpler demonstrations (e.g., current-carrying wires or solenoids) illustrate the same principles more effectively.Historical Context:The concept was experimentally verified by Henry Rowland in 1878, who measured the magnetic field of a rotating charged disk to confirm that moving charges produce magnetic fields. This experiment is rarely replicated today due to its complexity and the reliability of electromagnetic theory.Modern experiments focus on more practical or advanced applications, like dynamos or magnetic resonance, rather than revisiting this fundamental demonstration.Search Limitations:The search results provided don't include a direct video of this experiment. While there are references to related experiments (e.g., Faraday's disk, dynamo experiments, or rotating charged rings), none specifically match the charged disk setup.Online platforms like YouTube may have relevant content, but no specific video was identified in the results or general web knowledge up to April 16, 2025.
I couldn't find any videos showing an experiment with a spinning electrically charged disk generating a magnetic field. Would you like to try searching with different keywords or phrasing? I'm here to help you find the content you're looking for!
Experimental Challenges:Small Magnetic Field: Even with a highly charged disk (e.g., 20 pF at 10 kV, yielding 2 μC) spinning at 100 Hz, the resulting current is small (~0.2 mA), producing a weak magnetic field that requires sensitive detectors.
The concept was experimentally verified by Henry Rowland in 1878, who measured the magnetic field of a rotating charged disk to confirm that moving charges produce magnetic fields. This experiment is rarely replicated today due to its complexity and the reliability of electromagnetic theory.
The magnetic field sensor (magnetometer) in a typical smartphone is quite sensitive for consumer applications, though not as precise as scientific instruments. Here's a breakdown:Typical Sensitivity and Specs:Resolution: ~0.1 to 1 microtesla (?T)Full-scale range: Usually around ?50 to ?1000 ?TEarth?s magnetic field: ~25 to 65 ?T depending on location, so smartphone sensors are designed to easily detect that range.Key Points:They can detect changes in magnetic fields from small magnets, metal objects, and even nearby wires with current.They're not sensitive enough to detect extremely weak magnetic fields, like brain waves or the magnetic field from a single wire unless it's carrying significant current.Interference from nearby electronics or magnets can affect accuracy.Modern magnetometers are typically 3-axis (detect X, Y, Z directions).Use cases in phones:Compass functionalityMetal detectors (some apps use it)Magnetic anomaly detectionOrientation and navigation supportIf you're thinking of detecting something specific (like an electron beam?s field, or hidden wiring, etc.), I can help estimate whether a phone magnetometer would be sufficient. Want to test a specific field strength or setup?
Interference from nearby electronics or magnets can affect accuracy.
If you're thinking of detecting something specific (like an electron beam?s field, or hidden wiring, etc.), I can help estimate whether a phone magnetometer would be sufficient. Want to test a specific field strength or setup?
Anyone else would have checked the published specification of a phone. QuoteInterference from nearby electronics or magnets can affect accuracy.and spot bullshit. What, pray, is a "significant" current? QuoteIf you're thinking of detecting something specific (like an electron beam?s field, or hidden wiring, etc.), I can help estimate whether a phone magnetometer would be sufficient. Want to test a specific field strength or setup?in other words, if you tell ChatGPT the answer, it will tell you the answer. The ultimate management consultant!
In this video I show you how the field shifts when magnets are rotated with a colour gradient magnetic viewing film.
This is the second video where I show you how the field shifts when magnets are rotated with a colour gradient magnetic viewing film.
We?re all taught that moving charges create magnetic fields.But 200 years ago, Andr?-Marie Amp?re discovered something deeper: a direct force law between currents ? one that explained both attraction and repulsion without invoking fields at all.James Clerk Maxwell called it ?one of the most brilliant achievements in science.?And yet, within a few decades, it was forgotten ? replaced by the field-based picture of Faraday, Grassmann, Neumann, Lorentz, and finally Maxwell?s own equations.So what exactly did Amp?re see in his experiments?Why did physics turn its back on it?And what would it mean if he ? and later defenders like Wilhelm Weber, Andr? Assis, and Peter & Neal Graneau ? were right?