The Lorentz Force: Physics of Electromagnetism and Moving Charges
Explore the Lorentz force and the physics of electromagnetism. Learn how magnetic fields interact with moving charges to power motors and create the Northern Lights.
Best quote from The Lorentz Force: Physics of Electromagnetism and Moving Charges
The magnetic force is like a cosmic steering wheel that has no gas pedal and no brakes; because it is always perpendicular to your velocity, it can only change your direction, never your speed.
This audio lesson was created by a BeFreed community member
Magnetic Fields • Magnetic forces on moving charges (Lorentz force) • Magnetic force on current-carrying wires • Motion of charged particles in magnetic fields (cyclotrons, velocity selectors) • Magnetic field lines and Gauss’s Law for magnetism
Frequently Asked Questions
The Lorentz force is a fundamental principle of electromagnetism that describes the force exerted on moving charges within a magnetic field. Unlike gravity, which acts on objects regardless of their state of motion, this force only 'sees' and interacts with particles like electrons when they are in motion. It acts as a sideways push that serves as the bedrock for modern technology, influencing everything from industrial electric motors to advanced medical devices that steer electron beams.
Velocity is the essential trigger for the Lorentz force. If an electron is stationary next to a magnet, no interaction occurs and the particle remains still. However, the moment the electron starts moving, the magnetic field intervenes and yanks it sideways. This unique relationship between motion and force means the magnetic field acts like a silent observer that only catches and influences charges once they achieve a certain velocity, making it fundamentally different from forces like gravity.
The Lorentz force is responsible for many natural phenomena and technological advancements we see today. It is the specific force on moving charges that allows electric motors to function and enables the steering of electron beams in specialized medical equipment. Additionally, this interaction between magnetic fields and moving particles is the reason the Northern Lights occur in the atmosphere. Without the physics of the sideways push, much of the technology we rely on would not exist.
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From Columbia University alumni built in San Francisco
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"Perfect balance between learning and entertainment. Finished ‘Thinking, Fast and Slow’ on my commute this week."
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"Reading used to feel like a chore. Now it’s just part of my lifestyle."
"Feels effortless compared to reading. I’ve finished 6 books this month already."
"BeFreed turned my guilty doomscrolling into something that feels productive and inspiring."
"BeFreed turned my commute into learning time. 20-min podcasts are perfect for finishing books I never had time for."
"BeFreed replaced my podcast queue. Imagine Spotify for books — that’s it. 🙌"
"It is great for me to learn something from the book without reading it."
"The themed book list podcasts help me connect ideas across authors—like a guided audio journey."
"Makes me feel smarter every time before going to work"
"Instead of endless scrolling, I just hit play on BeFreed. It saves me so much time."
"I never knew where to start with nonfiction—BeFreed’s book lists turned into podcasts gave me a clear path."
"Perfect balance between learning and entertainment. Finished ‘Thinking, Fast and Slow’ on my commute this week."
"Crazy how much I learned while walking the dog. BeFreed = small habits → big gains."
"Reading used to feel like a chore. Now it’s just part of my lifestyle."
"Feels effortless compared to reading. I’ve finished 6 books this month already."
"BeFreed turned my guilty doomscrolling into something that feels productive and inspiring."
"BeFreed turned my commute into learning time. 20-min podcasts are perfect for finishing books I never had time for."
"BeFreed replaced my podcast queue. Imagine Spotify for books — that’s it. 🙌"
"It is great for me to learn something from the book without reading it."
"The themed book list podcasts help me connect ideas across authors—like a guided audio journey."
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"Instead of endless scrolling, I just hit play on BeFreed. It saves me so much time."
"I never knew where to start with nonfiction—BeFreed’s book lists turned into podcasts gave me a clear path."
"Perfect balance between learning and entertainment. Finished ‘Thinking, Fast and Slow’ on my commute this week."
"Crazy how much I learned while walking the dog. BeFreed = small habits → big gains."
"Reading used to feel like a chore. Now it’s just part of my lifestyle."
"Feels effortless compared to reading. I’ve finished 6 books this month already."
"BeFreed turned my guilty doomscrolling into something that feels productive and inspiring."
"BeFreed turned my commute into learning time. 20-min podcasts are perfect for finishing books I never had time for."
"BeFreed replaced my podcast queue. Imagine Spotify for books — that’s it. 🙌"
"It is great for me to learn something from the book without reading it."
"The themed book list podcasts help me connect ideas across authors—like a guided audio journey."
"Makes me feel smarter every time before going to work"
