Calculating Electron Velocity in a Magnetic Field

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Homework Help Overview

The discussion revolves around a physics problem related to calculating the velocity of electrons in a magnetic field, specifically within the context of Thomson's electromagnetic experiment. The problem involves determining the strength of the electric field between deflection plates and subsequently finding the speed of electrons as they enter this region.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to calculate the electric field strength and is working on determining the electron velocity. They express uncertainty about applying the relevant formulas and mention having the answers in the back of the book but are struggling to reach them.
  • Some participants question the original poster's familiarity with Thomson's experiment and seek additional resources, such as diagrams, to aid understanding.
  • Others suggest that the information in the provided links may assist in solving the velocity question.

Discussion Status

The discussion is ongoing, with participants exploring different aspects of the problem. Some guidance has been offered regarding the need for the velocity to calculate the magnetic force, and links to external resources have been shared to support the original poster's understanding.

Contextual Notes

There is mention of specific values such as the magnetic field strength and potential difference, but the original poster indicates they are unsure about applying the formulas correctly. The discussion reflects a lack of explicit consensus on the approach to finding the electron velocity.

ekinnike
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This question is in my yr 12 homework textbook.

q21.keyword e=exponential in case if i confused u .
In a tube similar to that used in the Thomson's electromagnetic experiment, a magnetic of 1.00 x 10e-2 T is sufficient to allow the electrons to pass through the electric delfection plates. The plates are 10 mm apart and have a potential difference of 300 V across them.
(a) what is the strength of the electric field between the plates? 3x10e4 vm(i did and checked with the book)no problem with this question...

(b)What was the speed of the lectrons as they entered the region between the plates? working on...
(c) what was the strength of the magnetic force acting on the electrons.
havent try
i only have some formulas to work with it
F = qvBsinO v=velocity

E = V/d V=voltage

v= B/E <--- not quite sure about this .i tried to apply for (b) but didnt quite get the answer. I have answer at the back of book but i can't work it out...
thanks in advanced
 
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I'm not familiar with Thomson's electromagnetic experiment. Could you provide a link to a diagram? You are correct that you need the velocity v from answer (b) in order to calculate the magnetic force F=qvXB.
 
berkeman said:
I'm not familiar with Thomson's electromagnetic experiment. Could you provide a link to a diagram? You are correct that you need the velocity v from answer (b) in order to calculate the magnetic force F=qvXB.
http://library.thinkquest.org/13394/angielsk/athompd.html <-- i just googled it. not sure if it useful
 
Last edited by a moderator:
ekinnike said:
http://library.thinkquest.org/13394/angielsk/athompd.html <-- i just googled it. not sure if it useful
Well, it certainly looks like there is enough info in that link to help you solve your homework problem. Especially the explanation and equations about 3/4 of the way down. Don't they help you with question (b) about the required velocity...?
 
Last edited by a moderator:

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