An insulating spherical shell with inner radius $\backslash ($ a $\backslash )$ and outer radius $\backslash ($ b $\backslash )$ is uniformly charged with charge density $\backslash (\backslash$rho $\backslash ).$ Determine the electric field at:

a$)(4$ marks$)\backslash ($ ab $\backslash )$

c$)(2$ marks$)$ Draw a sketch and show the relevant surfaces and electric field vectors.

Provide your answer symbolically.