Feynman's apparent paradox - Electromagnetism

In summary, the conversation discusses Feynman's "apparent" paradox in chapter 17 of "Feynman Lectures on Physics - Vol II". It involves the rotation of a disc when the current from a battery is stopped, which appears to violate the law of conservation of angular momentum. However, it is explained that the electromagnetic field can have angular momentum, thus resolving the paradox.
  • #1
Shan Ravi
11
0
Feynman's "apparent" paradox - Electromagnetism

This is the paradox discussed in chapter 17 of "Feynman Lectures on Physics - Vol II"

http://www.flickr.com/photos/37453425@N07/3447068420/

Say suppose the battery drains out or somehow you stop the current outta the battery. By electromagnetic laws, the disc ought to rotate... but then that violates the law of conservation of angular momentum (since no external torque is being applied)

I suggest you read the "apparent" paradox in the book.
 
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  • #3


No paradox, the electromagnetic field can have angular momentum.
 
  • #4


Ooh... thnx :)
 

1. What is Feynman's apparent paradox in Electromagnetism?

Feynman's apparent paradox in Electromagnetism is a thought experiment proposed by physicist Richard Feynman. It involves placing a charged particle in a uniform magnetic field and observing its motion. According to classical electromagnetism, the particle should experience a force perpendicular to its velocity and move in a circular path. However, according to special relativity, the particle's motion should not be affected by the magnetic field. This apparent contradiction is known as Feynman's apparent paradox.

2. How does Feynman's apparent paradox challenge classical electromagnetism?

Feynman's apparent paradox challenges classical electromagnetism by highlighting the limitations of the theory. Classical electromagnetism does not take into account the effects of special relativity, which becomes significant at high velocities. The paradox shows that the classical understanding of how charged particles interact with magnetic fields is not always accurate.

3. What is the solution to Feynman's apparent paradox?

The solution to Feynman's apparent paradox lies in the concept of the Lorentz force, which combines the effects of electric and magnetic fields on a charged particle. When considering special relativity, the Lorentz force takes into account the relativistic effects on the particle's motion and explains the seemingly contradictory behavior observed in the thought experiment.

4. How does Feynman's apparent paradox relate to other paradoxes in physics?

Feynman's apparent paradox is just one of many paradoxes in physics that arise when classical theories are combined with the principles of special relativity and quantum mechanics. These paradoxes often serve as a catalyst for new discoveries and advancements in our understanding of the universe. They also highlight the need for more comprehensive theories that can explain all the observed phenomena.

5. What implications does Feynman's apparent paradox have for our understanding of the universe?

Feynman's apparent paradox, along with other paradoxes in physics, challenges our current understanding of the universe and shows that there are still mysteries to be solved. It also highlights the need for more comprehensive and unified theories that can explain all the observed phenomena, including the effects of special relativity and quantum mechanics. This paradox has led to further research and advancements in the field of physics and has expanded our understanding of the fundamental laws of nature.

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