An isolated solid metal sphere is given a net positive charge
PHYSICS · Multi-part · CBSE · Physics · Electrostatic Potential and Capacitance · Electrostatic Potential and Capacitance
Problem
An isolated solid metal sphere is given a net positive charge. A student produces a discrete vector map of the electric field both inside and outside the sphere. No arrows appear anywhere inside the metal. Outside the sphere the arrows point radially outward, and their lengths decrease with increasing distance from the surface.
(a) Explain why the electric field inside the metal sphere is zero even though the sphere carries excess charge.
(b) Describe how the direction of the field vectors right at the surface relates to the distribution of excess charge on the sphere.
(c) The student repeats the experiment with an insulating sphere of the same radius that carries the same net positive charge uniformly throughout its volume. Qualitatively describe how the vector map inside the insulating sphere would differ from the map obtained for the metal sphere, and explain the physical reason for the difference.