Coulomb's Law: why is $k = \dfrac{1}{4\pi\epsilon_0}$
83262
Why is there a factor of $4\pi$ in certain force equations?
61686
Noether's first theorem and classical proof of electric charge conservation
122670
Explanation for $E~$ not falling off at $1/r^2$ for infinite line and sheet charges?
43184
Using the Residue Theorem to Prove that $\int^{2\pi}_{0} \frac{1}{(a+\cos\theta)^{2}} d \theta=\frac{2\pi a}{(a^{2}-1)^{3/{2}}}.$
15477
Nice proofs of $\zeta(4) = \frac{\pi^4}{90}$?
3406
Prove that $\frac{\partial x}{\partial y} \frac{\partial y}{\partial z} \frac{\partial z}{\partial x} = -1$ and verify ideal gas law
16096
What does 1/k represent regarding Newtons Law of Cooling?
126539
What is the range of the validity of Coulomb's law?
139057
Showing that $\frac{1}{2\pi}\int^{2\pi}_{0}(2\cos\theta)^{2n}d\theta=\frac{(2n)!}{n!n!}$
98326
Why is the Derangement Probability so Close to $\frac{1}{e}$?
41603
How is Gauss' Law (integral form) arrived at from Coulomb's Law, and how is the differential form arrived at from that?
6848
The strange thing about the maximum in Planck's law
157091
Photons in coulomb field
120719
Why isn't it $E \approx 27.642 \times mc^2$?
26154
Motivation for Ramanujan's mysterious $\pi$ formula
81178
Why are the two outer charge densities on a system of parallel charged plates identical?
3356
Why $\sum_{k=0}^m x^k $ is equal to $\dfrac{x^{m+1}-1}{x-1} $?