Magnetic Field Deflection: Why No Work Done?

Click For Summary

Homework Help Overview

The discussion revolves around the concept of magnetic fields and their interaction with charged particles, specifically focusing on why a magnetic field does not perform work on an electron beam despite causing deflection.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the relationship between magnetic force, velocity, and the concept of work. Questions arise regarding the meaning of terms like "trace of the beam" and how it relates to the velocity of the beam.

Discussion Status

Some participants have provided insights into the properties of magnetic forces and cross products, while others are questioning the reasoning behind the choices presented. There is an ongoing exploration of the implications of the perpendicular nature of magnetic force and its effects on the motion of the beam.

Contextual Notes

Participants are navigating through multiple answer choices and reflecting on their understanding of the concepts involved, with some indicating confusion over the correct interpretation of the problem.

artupayam
Messages
3
Reaction score
0
A magnetic field deflects an electron beam, but it can not do any work on the beam. Why?

a. since the magnetic force on the beam is zero
b. since the acceleration of the beam is zero
c. since the magnetic force is perpendicular to the trace of the beam
d. none of them
 
Physics news on Phys.org
What formula describes the magnetic force on a moving charge?
 
Recall that the formula for a force of a magnetic field on a charged particle is given by:

F = qv X B , where v and B are vectors.

Also recall the properties of cross products of vectors.
 
Last edited:
Wrong Answer

Initially I chose d. since the magnetic force is perpendicular to the velocity of the beam. But it was the wrong answer so I took it off from the choices.
 
What do you think "trace of the beam" means? How does that relate to velocity?
 
Artupayam, it seems to me you were thinking along the right lines ... not sure why that didn't lead you to the right answer.

You should be able to eliminate 2 more by default. So only possible answer is..?
 
Ok I see, thanks you guys.
 

Similar threads

Replies
4
Views
1K
  • · Replies 11 ·
Replies
11
Views
3K
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
966
Replies
14
Views
3K
Replies
16
Views
2K
  • · Replies 29 ·
Replies
29
Views
4K
Replies
8
Views
3K
  • · Replies 5 ·
Replies
5
Views
2K