Electric potential and electric field strength are key concepts in electrostatics, particularly regarding their behavior within and outside charged spheres. Inside a uniformly charged sphere, the electric field intensity is zero due to the symmetrical distribution of charge, which cancels out the field lines. The relationship between electric potential and distance shows that potential decreases with increasing distance from a point charge, typically represented as potential proportional to 1/r. The potential difference is directly related to the electric field intensity, which is inversely proportional to distance. Understanding these principles is essential for mastering concepts in advanced level physics.