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 OO. A probe measures the magnitude EE of the electric field at several distances rr from OO; the field is found to point radially outwards everywhere. The readings are Data (distance rr, field magnitude EE): r=1.0 cmr=1.0\,\mathrm{cm}, E=5.75×103 V m−1E=5.75\times10^{3}\,\mathrm{V\,m^{-1}}; r=2.0 cmr=2.0\,\mathrm{cm}, E=11.5×103 V m−1E=11.5\times10^{3}\,\mathrm{V\,m^{-1}}; r=4.0 cmr=4.0\,\mathrm{cm}, E=23.0×103 V m−1E=23.0\times10^{3}\,\mathrm{V\,m^{-1}}; r=6.0 cmr=6.0\,\mathrm{cm}, E=20.0×103 V m−1E=20.0\times10^{3}\,\mathrm{V\,m^{-1}}; r=10.0 cmr=10.0\,\mathrm{cm}, E=7.19×103 V m−1E=7.19\times10^{3}\,\mathrm{V\,m^{-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 RR. ((b)) Find the total charge QQ of the ball. ((c)) Find the uniform volume charge density ρ\rho.

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