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## Homework Statement

e is charge

epsilon is permittivity

## Homework Equations

[tex]e^2 = 4\pi \epsilon GM^2[/tex]

## The Attempt at a Solution

This is just a question really because I am a bit confused about something. Was reading up on the fine structure constant and apparently the fine structure constant is

[tex]\alpha = \frac{e^2}{GM^2}[/tex]

I know it is supposed to be dimensionless, but where did epsilon go? Shouldn't it be

[tex]\frac{e^2}{\epsilon GM^2}[/tex]

Or has epsilon been set to 1?