type(s) of charge distribution for spherical and cylindrical gaussian surfaces

[yanyin]

I have a new question:
"In applying Gauss's Law describe the types(s) of charge distribution for which (a) a spherical gaussian surface is useful and (b) a cylindrical gaussian surface is useful"
please help!

[Integral]

Seems pretty obvious. Use a Spherical surface for objects with spherical symmetry and cylindrical surface for objects with a cylindrical symmetry.