If a spherical shell has a uniform volume density of 1.84nC/m^3, inner radius a=.1m, outer radius b=.2m, what is magnitude of electric field at radial distances r=a, r=b, r=3b

Answer 1

Gauss Law:
at r=a, no charge is enclosed, zero E
at r=b, enclosed charge=Q=4/3 PI (b^3-a^3)*1.84nC, so figure E from kQ/b^2
E= 4kPI/3(b^3-a^3)*1.84E-9/b^2

at r=3b
E= 4kPI/27(b^3-a^3)*1.84E-9/b^2

check all that.