How does the electromagnetic force work? How can it both attract and repel?
Answers
related.
Finally, Dutchman Hendrik Lorentz calculated the force acting on a charged particle in an electromagnetic field in 1892.
When scientists worked out the structure of the atom in the early 20th century, they learned that subatomic particles exerted electromagnetic forces on each other. For example, positively charged protons could hold negatively charged electrons in orbit around the nucleus. Furthermore, electrons of one atom attracted protons of neighboring atoms to form a residual electromagnetic force, which prevents you from falling through your chair.
But how does electromagnetism work at an infinite range in the large world and a short range at the atomic level? Physicists thought that photons transmitted electromagnetic force over large distances. But they had to devise theories to reconcile electromagnetism at the atomic level, and this led to the field of quantum electrodynamics (QED). According to QED, photons transmit electromagnetic force both macroscopically and microscopically; however, subatomic particles constantly exchange virtual photons during their electromagnetic interactions.
But electromagnetism can't explain how the nucleus holds together. That's where nuclear forces come into play.
Finally, Dutchman Hendrik Lorentz calculated the force acting on a charged particle in an electromagnetic field in 1892.
When scientists worked out the structure of the atom in the early 20th century, they learned that subatomic particles exerted electromagnetic forces on each other. For example, positively charged protons could hold negatively charged electrons in orbit around the nucleus. Furthermore, electrons of one atom attracted protons of neighboring atoms to form a residual electromagnetic force, which prevents you from falling through your chair.