Charged Particles in Electric and magnetic fields

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Homework Help Overview

The problem involves an electron being accelerated through a potential difference of 15.0 kV and subsequently moving in a magnetic field of strength 2.35 T. The focus is on determining the electron's final speed before it enters the magnetic field.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the relationship between the potential difference and the electron's speed, with one participant attempting to calculate the speed using the equation derived from the work-energy principle. Others question the relevance of the magnetic field to the problem and express concerns about insufficient information for further calculations.

Discussion Status

The discussion is ongoing, with various interpretations of the problem being explored. Some participants have provided insights into the work-energy relationship, while others are seeking clarification on the significance of the magnetic field and the need for additional information to proceed with calculations.

Contextual Notes

Participants are navigating the implications of the problem setup, particularly regarding the timing and effects of the magnetic field on the electron's motion. There is an acknowledgment of the need for specific parameters to fully resolve the question.

sarahdee
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Homework Statement


An electron, initially at rest, is accelerated through a potential diff of 15.0 kv. It is then allowed to circulate at right angles to a uniform magnetic field of strength 2.35 T.
Calculate the electrons final speed before entering the magnetic field.


Homework Equations



f= eq
f=bqv

The Attempt at a Solution



(15000)q = q(2.35)v
(15000)= 2.35v
v= approx. 6383
 
Last edited:
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Yeah OK so what do you know about this topic?
If I understand this correctly, the question is what will the speed of the electron be after it has been accelerated by 15kV's, if it started with v = 0.
 
I just edited my original post,
to show how I worked it out before.
 
But how does the magnetic field have any significance? Doesn't the question ask the speed BEFORE the electron goes into the magnetic field?
 
But won't that leave me with insufficient info?

because I then have to calculate a with (f=ma), using the f=eq formula.
But i will require the time that it is in the field to know it's final speed
 
All you need to know is the total work done on the electron (W=U*q) and and the work-theory or whatever you call it when dE = W. So this gives you the equation U*q = .5*m*v^2 - 0, where q is the charge of the electron and m is it's mass.
 

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