How can a magnetic field move a charged particle?

In summary, the conversation discusses ways to prove that a magnetic field can increase the speed of a charged particle. Some examples include using an induced electric field or launching a ring with an opposite magnetic field. The conversation also mentions a demonstration of a rail gun that uses a magnetic field to accelerate a metal ring, which is made up of charged particles.
  • #1
Smittens
1
0
Hi,

So in order to earn a few crucial points back from my teacher I need to prove that a magnetic field can increase the speed of a charged particle. I've made a list of a couple methods so far (see examples below) but am hoping that you all could help me think of a few more.

Now I know (or at least have been told, and can't think of an exception) that it is impossible for a magnetic field to directly increase the speed of a charged particle. This makes sense, since the force of a magnetic field is perpendicular to the particle's velocity it will only change the direction of its movement.

However, I have been considering the angle of a magnetic field indirectly speeding up a charged particle. For example (here are some of the ones I've thought of)

- A magnetic field can induce an electric field, and an electric field could move the charged particle
- A magnetic field can be induced in a ring opposite of an already existing magnetic field. If the ring in question is resting on a cylinder, the ring will be launched off the cylinder. If our charged particle in question is resting on the ring when it is launched, the charged particle will speed up as it accelerates. (This thought was based on a demonstration in class)

I'm not quite sure if this thread belongs in the right place, it's not exactly a homework question, but it is in the same idea. Any assistance would be GREATLY appreciated, and the crazier any ideas, the better! (so long as they work :))

Thanks,
Caleb "Smittens" Martin
 
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  • #2
Smittens said:
So in order to earn a few crucial points back from my teacher I need to prove that a magnetic field can increase the speed of a charged particle. I've made a list of a couple methods so far (see examples below) but am hoping that you all could help me think of a few more.

How about this:

Have you ever seen a demonstration with a simple rail gun, such as the one depicted in the webpage below?

http://ww2.slcc.edu/schools/hum_sci/physics/tutor/2220/em_induction/ [Broken]

Well, in that case you've got a magnetic field accelerating a metal ring, which is just a collection of charged particles. :wink:
 
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  • #3


Hi Caleb,

Great question! The key to understanding how a magnetic field can move a charged particle lies in the concept of the Lorentz force. This force is the combination of the electric and magnetic forces acting on a charged particle in a magnetic field. The Lorentz force is given by the equation F = q(E + v x B), where q is the charge of the particle, E is the electric field, v is the velocity of the particle, and B is the magnetic field.

As you mentioned, a magnetic field alone cannot directly increase the speed of a charged particle. However, when the particle is moving in a magnetic field, the Lorentz force will cause it to experience a change in direction, which in turn can cause it to accelerate and increase its speed. This is similar to how a car makes a turn on a curved road - the car's velocity changes direction, causing it to accelerate towards the center of the curve.

Now, to answer your question about how a magnetic field can indirectly speed up a charged particle, you are correct in saying that an electric field can be induced by a changing magnetic field. This is known as electromagnetic induction. This induced electric field can then exert a force on the charged particle, causing it to accelerate and increase its speed. This is the principle behind devices such as electric generators and motors.

Another way a magnetic field can indirectly affect the speed of a charged particle is through the phenomenon of magnetic resonance. In this process, a magnetic field is used to manipulate the spin of charged particles, such as electrons or protons, in a substance. By controlling the strength and direction of the magnetic field, scientists can speed up or slow down these particles, which is crucial in applications such as MRI machines and particle accelerators.

I hope this helps to provide some additional ideas for your list! Keep exploring the fascinating world of electromagnetism and its effects on charged particles. Good luck with your assignment.

Best,
 

1. How does a magnetic field affect a charged particle?

When a charged particle enters a magnetic field, it experiences a force that is perpendicular to both its velocity and the direction of the magnetic field. This force causes the particle to move in a circular path, known as the Lorentz force.

2. How can a magnetic field change the direction of a charged particle?

A magnetic field can change the direction of a charged particle because the force it experiences is always perpendicular to its motion. As the particle moves in a circular path, it continuously changes direction, resulting in a curved trajectory.

3. Can a magnetic field affect the speed of a charged particle?

No, a magnetic field does not directly affect the speed of a charged particle. However, it can indirectly influence the speed by changing the direction of the particle's motion. If the magnetic force is strong enough, it can cause the particle to move in a tighter or wider circular path, resulting in a change in its speed.

4. How does the strength of a magnetic field impact the movement of a charged particle?

The strength of a magnetic field directly affects the amount of force a charged particle experiences. A stronger magnetic field will result in a greater force, causing the particle to move in a more pronounced curved path.

5. Can a magnetic field move a charged particle in a straight line?

No, a magnetic field cannot move a charged particle in a straight line. The force it exerts on the particle is always perpendicular to its velocity, resulting in a circular motion. In order for a charged particle to move in a straight line, it must experience a force in the same direction as its motion.

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