A static, spherically symmetric cloud of charge sits in vacuum with its centre at the…
PHYSICS · Multi-part · Fermi University Physics · Electricity, Magnetism & Electromagnetism · Electrostatic fields and potential · Electrostatic fields and potential
Electricity, Magnetism and Electromagnetism, Ch Electric flux and Gauss's law
Problem
A static, spherically symmetric cloud of charge sits in vacuum with its centre at the point O. A probe measures the magnitude E of the electric field at several distances r from O; the field is found to point radially outwards everywhere. The readings are Data (distance r, field magnitude E): r=1.0cm, E=5.75×103Vm−1; r=2.0cm, E=11.5×103Vm−1; r=4.0cm, E=23.0×103Vm−1; r=6.0cm, E=20.0×103Vm−1; r=10.0cm, E=7.19×103Vm−1. Translate these readings into a charge distribution. In your working name the Gaussian surface you use and the symmetry that justifies it.
((a)) Show that the readings fit a ball of uniform volume charge density, the simplest distribution consistent with them, and find its radius R.
((b)) Find the total charge Q of the ball.
((c)) Find the uniform volume charge density ρ.