Say we have a +Q charge located inside an isolated spherical conducting body and I want to know the E field at some point P outside the conducting body.
I reliase that since this is a conducting body, the E field inside is zero. So by Gauss's Law, ##Q_{enclosed} = 0##. The only way for this to happen is if there is an induced charge -Q on the inner surface of the body.
My question is: if I wanted to compute the E field at point P a distance r away from the surface of the body, why do I use R + r as my distance from the charge in the E field formula? (R the radius of the conducting body).
I reliase that since this is a conducting body, the E field inside is zero. So by Gauss's Law, ##Q_{enclosed} = 0##. The only way for this to happen is if there is an induced charge -Q on the inner surface of the body.
My question is: if I wanted to compute the E field at point P a distance r away from the surface of the body, why do I use R + r as my distance from the charge in the E field formula? (R the radius of the conducting body).