What Are the Correct Units for the Larmor Formula?

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SUMMARY

The Larmor formula, represented as P = (μ₀ q² a²) / (6π c), calculates the power radiated by a charged particle undergoing acceleration. The correct units for power in this formula are watts, which correspond to kg m² s⁻³. The initial confusion arose from an error in the units of acceleration, where a² was mistakenly calculated as m² s⁻² instead of the correct m² s⁻⁴. This highlights the importance of accurate dimensional analysis in physics.

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  • Understanding of the Larmor formula in classical electrodynamics
  • Familiarity with SI units and dimensional analysis
  • Knowledge of electromagnetic theory, specifically the role of charge and acceleration
  • Basic principles of power calculation in physics
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  • Study the derivation and applications of the Larmor formula in classical electrodynamics
  • Learn about dimensional analysis techniques in physics
  • Explore the relationship between acceleration and power in electromagnetic radiation
  • Investigate common errors in unit conversions and dimensional analysis in scientific calculations
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Physics students, educators, and professionals in the field of electromagnetism who seek to deepen their understanding of the Larmor formula and its applications in power calculations.

bdforbes
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The Larmor formula is:

P=\frac{\mu_0 q^2 a^2}{6\pi c}

When I checked the units of this, I got [kg m^2 s^-1]. If it is in watts, shouldn't it be [kg m^2 s^-3]? I was pretty thorough in putting everything in SI units.

\mu_0 is N/A^2 or kg m s^-2 A^-2.
q^2 is C^2 or A^2 s^2
a^2 is m^2 s^-2
c is m s^-1

Have I made a stupid error, or is this just the wrong way of doing the dimensional analysis?

This is not homework.
 
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I don't think the formula is right.

edit: Never mind. :P
 
Last edited:
The units of acceleration are m/s^2 not m/s, so the units of a^2 are [/itex]m^2/s^4[/itex] not [/itex]m^2/s^2[/itex].
 
Stupid error it is then, thanks :P. You'd think after 4 years of uni I might be able to get that one right...
 

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