Tv electron and earth magnetic field

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Homework Help Overview

The problem involves the interaction between electrons in a television tube and the Earth's magnetic field. The electrons have a specified energy and are moving in a particular direction, while the magnetic field's vertical component is also defined.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss the application of the right-hand rule to determine the direction of the magnetic force on the electrons. There is confusion regarding the strength of the magnetic field and its implications for the problem.

Discussion Status

Multiple interpretations of the force direction are being explored, with some participants suggesting north and others proposing south due to the negative charge of the electron. Clarifications regarding the magnetic field's strength have also been raised.

Contextual Notes

There is a noted discrepancy regarding the strength of the Earth's magnetic field, with one participant correcting the value from teslas to microteslas, indicating potential confusion about the problem's parameters.

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Homework Statement


The electrons in the beam of a television tube have an energy of 23.0 keV. The tube is oriented so that the electrons move horizontally from west to east. At the electron's latitude the vertical component of the Earth's magnetic field points down with a magnitude of 57.6 T. What is the direction of the force on the electrons due to this component of the magnetic field?


Homework Equations





The Attempt at a Solution


The options are up, down, north, south, west,east.
I chose north because B is down(middle finger), pointer finger horizontal and therefore thumb points north. Why is that wrong?
 
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57.6 T
Is an awfully strong magnetic field. The Earth's field is relatively weak.

Nevertheless, the velocity of the electron is west to east (horizontal) and the magnetic field is down (vertical) which leaves either N or S, based on

F = q (v x B), where q is the charge, v is the velocity and B is magnetic field strength.
 
With right hand rule I get north, but it is incorrect!
Sorry it should be micro teslas!
 
Last edited:
Actually shouldn't it be south because the negive from the charge of an electron flips the force the opposite direction.
 

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