Is the Potential Constant Inside a Spherical Conductor/Insulator?

[LocationX]

why is the potential constant inside a spherical conductor/insulator? Are there boundary conditions that needs to be satisfied in order to make the potential zero?

this is just a general question since most of the physics problems that I do needs the potential to be constant inside the sphere.

 

[kreil]

the potential inside a spherical conductor is constant (at the value that it reaches at the surface of the sphere) because the E-field inside the conductor is zero.

In order to calculate the potential you need to choose a spot where the potential is zero as a reference point for the integral. Normally, choosing infinity works just fine. However, if you have a charge that goes to infinity (such as an infinitely long charged rod) the potential does not go to zero at infinity and the best choice is typically zero or an arbitrary point a.