This is a short post on forces, Coulombs, Gravitational and Plancks. I will be doing more on this in later posts but this is just a little result that I stumbled upon today. I am certain others have been down this road, but it is a nice result so I thought I would share it with you.
I am not going to go into full detail on how I got this one, it is mostly irrelevant to this post and I will cover it elsewhere. So to start, Planck force is defined as
F_p = \frac {c^4} {G} ...(1)
c- speed of light
G - gravitational constant
Coulombs force
F_c = \frac {e^2} {4 \pi \epsilon_0 r^2} ...(2)
e - charge on the electron
1 / 4\pi \epsilon_0 - Coulombs constant
r - distance between the electrons
Gravitational force
F_g = \frac {m_e^2 G} {r^2} ... (3)
m_e - mass of the electron
r and G are the same as those above
Dividing (3) by (2) gives
\frac {F_g} {F_c} = \frac {m_e^2 G 4 \pi \epsilon_0} {e^2} ...(4)
the r term has cancelled here.
Now let's take a look at r_e, the classic electron radius, given by
r_e = \frac {e^2} {4 \pi \epsilon_0 m_e c^2} ...(5)
We are going to do two things here, the first is to multiple (2) by r_e, while also replacing r with r_e to give
F_c r_e = \frac{e^2 r_e} { 4 \pi \epsilon_0 r_e^2}
we can now cancel the r_e on the right to give
F_c r_e = \frac{e^2} { 4 \pi \epsilon_0 r_e} ...(6)
now we put (5) into (6) to give
F_c r_e = \frac {e^2 4 \pi \epsilon_0 m_e c^2} { 4 \pi \epsilon_0 e^2}
most of this cancels to leave
F_c r_e = m_e c^2 = E ...(7)
Secondly put r_e into (2) in place of r and sub in its value from (5) giving
F_c = \frac {e^2 (4 \pi \epsilon_0)^2 m_e^2 c^4} { 4 \pi \epsilon_0 e^4}
after some cancelling this becomes
F_c = \frac { 4 \pi \epsilon_0 m_e^2 c^4} { e^2} ...(8)
divide this bu F_p to give
\frac {F_c} {F_p} = \frac { 4 \pi \epsilon_0 m_e^2 c^4 G} { c ^4 e^2}
cancelling leaves
\frac {F_c} {F_p} = \frac { 4 \pi \epsilon_0 m_e^2 G} { e^2} ...(9)
but this is just (4), so
\frac {F_c} {F_p} = \frac {F_g} {F_c} ...(10)
so when r = r_e we have
F_c^2 = F_p F_g ...(11)
Coulomb force squared is equal to the Planck Force multiplied by the gravitational force. Cool eh?
Wrote this while listening to this.
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