Motion of a charged particle in magnetic field

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Homework Help Overview

The discussion revolves around the motion of a charged particle in a magnetic field, specifically analyzing the behavior of a particle with charge -q and mass m as it enters and exits a magnetic field at different angles and speeds. The participants are exploring various properties of the motion, including the relationships between angles and speeds as well as the time spent in the field.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the implications of the Lorentz force and its vector form, questioning how to visualize the path of the particle as it enters the magnetic field at an angle. There are attempts to resolve components of motion and considerations of circular motion based on the magnetic force acting as centripetal force.

Discussion Status

There is an ongoing exploration of the particle's trajectory and the effects of the magnetic field on its motion. Participants are sharing insights about the nature of the paths taken by the particle and questioning assumptions about angles and components of velocity. Some guidance has been offered regarding the use of vector analysis and the relationship between the magnetic field and the velocity vector.

Contextual Notes

Participants express uncertainty about drawing the path of the particle for various angles of entry into the magnetic field, indicating a need for clarification on how to approach the problem without specific cases. The discussion includes references to the constraints of the problem setup and the need for a deeper understanding of the underlying physics principles.

Abhimessi10
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Homework Statement


A particle of charge -q and mass m enterd magnetic field B at A with speed v1 at an angle alpha and leaves the field at C with v2 at angle beta.Then,

a)alpha=beta
b)v1=v2
c)particle remains in the field for time t=(2m(pi-alpha))/qB
d)All of these

Please see image below

https://ibb.co/iLMrie

Abhimessi10fig.jpg

Homework Equations


F=qvB

The Attempt at a Solution


Really don't know how to do it.Tried resolving components.
 

Attachments

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Abhimessi10 said:

Homework Statement


A particle of charge -q and mass m enterd magnetic field B at A with speed v1 at an angle alpha and leaves the field at C with v2 at angle beta.Then,

a)alpha=beta
b)v1=v2
c)particle remains in the field for time t=(2m(pi-alpha))/qB
d)All of these

Please see image below

https://ibb.co/iLMrie

Homework Equations


F=qvB

The Attempt at a Solution


Really don't know how to do it.Tried resolving components.[/B]
Resolving components will not get you very far. Other than F=qvB, what else do you know about the motion of particles in magnetic fields? Can you draw the path connecting the entry and exit points of the particle?
 
kuruman said:
Resolving components will not get you very far. Other than F=qvB, what else do you know about the motion of particles in magnetic fields? Can you draw the path connecting the entry and exit points of the particle?

I don't know to draw the path for particles entering at general angles.just the case when angle=90, 0, and in between.
 
Abhimessi10 said:
I don't know to draw the path for particles entering at general angles.just the case when angle=90, 0, and in between.
OK. What kind of path do you get in these cases? Why is the path like that and like something else?
 
kuruman said:
OK. What kind of path do you get in these cases? Why is the path like that and like something else?
Because of magnetic force acting as centripetal force?
 
Abhimessi10 said:
Because of magnetic force acting as centripetal force?
Yes., and if the magnetic force is centripetal, what kind of path does the particle describe for as long as the force remains centripetal?
 
kuruman said:
Yes., and if the magnetic force is centripetal, what kind of path does the particle describe for as long as the force remains centripetal?

Depends on the angle velocity makes with the magnetic field.On a general basis i can say circular-kinda motion.
 
  • #10
Abhimessi10 said:
Depends on the angle velocity makes with the magnetic field.On a general basis i can say circular-kinda motion.
Look at your drawing. The magnetic field is directed into the screen and the velocity vector is in the plane of the screen. What do you think the angle between the magnetic field and the velocity is?
 
  • #11
kuruman said:
Look at your drawing. The magnetic field is directed into the screen and the velocity vector is in the plane of the screen. What do you think the angle between the magnetic field and the velocity is?
The sin alpha component of velocity is only perpendicular
and cos alpha would remain same?
 
  • #12
Abhimessi10 said:
The sin alpha component of velocity is only perpendicular
Imagine placing your index finger perpendicular to the face of an analog clock and keeping it fixed. What is the angle between your finger and the seconds hand at any time t? The seconds hand is like the velocity vector that changes direction in the plane of the screen and your index finger is like the magnetic field the direction of which is fixed.
 

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