Final answer:
The electric field generated by a spherical shell with a uniform surface charge density σ varies with the radius r.
Step-by-step explanation:
The correct answer is D. The electric field generated by a spherical shell with uniform surface charge density σ varies with the radius r.
For a spherical shell with uniform surface charge density σ, the electric field depends on the distance from the center of the shell. The electric field inside the shell is zero, while the electric field outside the shell is inversely proportional to the square of the distance from the center.
This can be determined using Gauss's law and the formula for the electric field created by a uniformly charged sphere.