You're sitting inside an uncharged, hollow spherical shell. sud- denly someone dumps a billion coulombs of charge on the shell, distributed uniformly. what happens to the electric field at your location?

When we place a charge at the center of the hollow sphere, the charge spreads all over its surface leaving no charge at the center or inside the shell. To determine the electric field, we draw a Gaussian surface inside the shell. The charge enclosed by this imaginary(Gaussian) surface is zero. Therefore, electric field at every point inside hollow spherical shell is zero. 

Full change in the electric plus system