What Magnetic Field Direction Will Allow the Electrons to Pass Through Without Being Deflected?
š§² Magnetic Force on a Charged Particle
The magnetic force acting on a moving charged particle is governed by the equation:
āF = q (āv Ć āB)
For electrons, the charge q is negative, that is:
q = āe
Hence, the magnetic force on an electron becomes:
āF = āe (āv Ć āB)
š Condition for No Deflection
The cross product āv Ć āB equals zero when the velocity vector āv and magnetic field vector āB are parallel or anti-parallel:
āv ā„ āB or āv anti-parallel to āB ā āv Ć āB = ā0
Therefore, the magnetic force becomes:
āF = āe (ā0) = ā0
ā Final Conclusion
Conclusion: When the magnetic field is directed along the direction of electron motion or exactly opposite to it, the cross product is zero. As a result, no magnetic force acts on the electrons, and they pass through the magnetic field without deflection.
This is a critical concept in electromagnetic theory and is often used in designing devices like velocity selectors, cathode ray tubes, and particle accelerators.
