In lab tests it was found that rats can detect electric fields of about 5.07 kN/C or more. If a point charge of 1.24 μC is sitting in a maze, how close must the rat come to the charge in order to detect it?
Require that k*Q/R^2 = 5070 N/C,
with Q = 1.24*10^-6 C, and solve for R.
You will need the Coulomb constant, k.
k= 8.988*10^9 Nm^2C^-2