Action reaction pair of magnetic force

[rtshah]

I am not able to understand reaction of magnetic force and how it is equal to qvb ?

 

[Dale]

When you start looking at fields you have to generalize Newton's third law. Basically Newtons third law expresses the conservation of momentum. While it may not make a lot of sense to talk about the force on a field, you can certainly talk about its momentum. Any force that the field exerts on matter causes an equal and opposite change in the momentum of the field.

 

[Kyler]

When you start looking at fields you have to generalize Newton's third law. Basically Newtons third law expresses the conservation of momentum. While it may not make a lot of sense to talk about the force on a field, you can certainly talk about its momentum. Any force that the field exerts on matter causes an equal and opposite change in the momentum of the field.

What is the momentum of the B field? I haven't heard of this concept yet. Any suggestions on some good reading in this subject?

 

[Dale]

Sure, I like this site
http://farside.ph.utexas.edu/teaching/em/lectures/node90.html

Duke also has a pretty good site on EM.

 

[sardar]

The action-reaction pair of magnetic force is a fundamental concept in physics, known as the Lorentz force law. According to this law, when a charged particle (q) moves through a magnetic field (B), it experiences a force (F) perpendicular to both its velocity (v) and the magnetic field. This force can be calculated using the equation F=qvB, where q is the charge of the particle, v is its velocity, and B is the strength of the magnetic field.

The reaction of the magnetic force refers to the equal and opposite force that the charged particle exerts on the magnetic field. This is in accordance with Newton's third law of motion, which states that for every action, there is an equal and opposite reaction. In this case, the action is the force exerted by the magnetic field on the charged particle, and the reaction is the force exerted by the charged particle on the magnetic field.

The equation F=qvB can be understood by considering the direction of the force. Since the force is perpendicular to both the velocity and the magnetic field, it is always at a right angle to the plane formed by these two vectors. This results in a circular motion of the charged particle, with the magnetic force acting as the centripetal force that keeps the particle in its circular path.

In summary, the reaction of the magnetic force is a fundamental aspect of the Lorentz force law and is essential for understanding the behavior of charged particles in a magnetic field. By considering the equal and opposite nature of the action-reaction pair, we can better understand the relationship between the charged particle, the magnetic field, and the resulting force.