What is the Electric Field Equation for an Electrified Sphere?

[omar558]

Homework Statement

The function that expresses the electric potential of a metallic electrified sphere is kQ/R if 0<r<R and kQ/r if r>R k=9 × 10^9 Nm2/c2
Find, starting from the electric potential function, the electric field function

Relevant Equations

Conceptual

I don't know if i can use V=E · d. I've read about gradient but i never used it so i was asking if there is another way to get tje electric field equation

 

[hutchphd]

Look up the expression for gradient in spherical coordinates and set to work. It is not complicated.

 

[rude man]

Or you could express V = V(Q,r) then us Gauss's theorem. For r<R remember where the charge lies on a metallic mass.