Speed of an Electron and the Magnetic field

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SUMMARY

The discussion focuses on calculating the speed of an electron with a kinetic energy of 1.60 keV and its corresponding magnetic field when it orbits with a radius of 24.0 cm. The correct formula for kinetic energy is identified as \( k = \frac{1}{2} mv^2 \), and the magnetic field is calculated using \( B = \frac{mvqr}{e} \). The initial attempt to find the speed resulted in an incorrect value of 4.627 km/s, indicating a misunderstanding of the equations involved. The correct approach requires proper application of the kinetic energy formula and the relationship between speed, mass, and charge of the electron.

PREREQUISITES
  • Understanding of kinetic energy equations in physics
  • Familiarity with the properties of electrons, including mass and charge
  • Knowledge of magnetic fields and their interaction with charged particles
  • Basic algebra for solving equations
NEXT STEPS
  • Review the derivation of kinetic energy formulas in classical mechanics
  • Study the Lorentz force and its application to charged particles in magnetic fields
  • Learn about the relationship between kinetic energy and velocity for electrons
  • Explore the concept of circular motion in magnetic fields and its mathematical implications
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Students studying physics, particularly those focusing on electromagnetism, as well as educators seeking to clarify concepts related to electron dynamics in magnetic fields.

mlsohani
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Homework Statement



An electron with kinetic energy 1.60 keV circles in a plane perpendicular to a uniform magnetic field. The orbit radius is 24.0 cm.
a Find the speed of the electron.
b Find the Magnetic Field

Homework Equations



k=1/(2mv^2)
B=mvqr

The Attempt at a Solution


I first converted keV to Joules which came out to be 2.5635 e-16 J

I then made the equation to solve for v : v=sqrt(1/2mk)

But I came out with the velocity being e22 4.627 km/s which is not right

PLease help!
 
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Hi mlshani,

mlsohani said:

Homework Statement



An electron with kinetic energy 1.60 keV circles in a plane perpendicular to a uniform magnetic field. The orbit radius is 24.0 cm.
a Find the speed of the electron.
b Find the Magnetic Field

Homework Equations



k=1/(2mv^2)

This equation does not look right to me; do you see what it needs to be?
 
No I thought that was the equation, at least that is the one on my physics book?
Is there another equation to find the speed of an electron?
 
(mV^2)/2
 
Thank you!

I can't believe I saw that equation as having everything in the denominator!

Thank you!
 

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