Answer to Question #186567 in Physics for Watermelon sugar high

Question

HOW many excess electrons must be added to an isolated spherical conductor 0.100 meters in diameter to produce an electric field of 1800N/C just outside the surface?

Answer 1

The field is

$$E=\frac{Q}{4\pi \epsilon_0r^2}=\frac{Ne}{4\pi \epsilon_0r^2},\\\space\\ N=\frac{4\pi \epsilon_0r^2E}{e}=1.25·10^{10}.$$