Magnetic Force on Electron: Unanswered Mystery

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SUMMARY

The magnetic force on an electron moving within a uniform magnetic field of 0.2T at a speed of 5x105 m/s cannot be definitively calculated without knowing the angle between the electron's velocity and the magnetic field. The formula used, Fm = |q| v B sin θ, indicates that the angle θ is crucial for determining the force. The calculated force of 1.6x10-14N assumes a 90-degree angle, which is not specified in the problem, leading to ambiguity in the result.

PREREQUISITES
  • Understanding of electromagnetic theory
  • Familiarity with the Lorentz force equation
  • Knowledge of vector components in physics
  • Basic concepts of magnetic fields and forces
NEXT STEPS
  • Study the Lorentz force law in detail
  • Learn about the effects of angle in magnetic force calculations
  • Explore vector analysis in electromagnetic contexts
  • Investigate applications of magnetic fields in particle physics
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This discussion is beneficial for physics students, educators, and anyone interested in understanding the principles of electromagnetism and the behavior of charged particles in magnetic fields.

dcgirl16
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an electron moves within a uniform magnetic field of .2T at a speed of 5x10^5 m/s. What is the magnetic force on the electron?

I used Fm=qvBSin and got 1.6x10^-14N but the answer is that it can't be determined with this info why not?
 
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dcgirl16 said:
an electron moves within a uniform magnetic field of .2T at a speed of 5x10^5 m/s. What is the magnetic force on the electron?

I used Fm=qvBSin and got 1.6x10^-14N but the answer is that it can't be determined with this info why not?

Because you don't know the angle between the velocity of the electron and the magnetic field! You are right that the magnitude of the magnetic field is [itex]F_m = |q| v B sin \theta[/itex] but without the angle [itex]\theta[/itex] you can't find the answer. (how did {\em you} get an answer? I bet that you used an angle equal to 90 degrees!)

Patrick
 

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