Someone argues: 'A dielectric sphere always weakens the field inside it
PHYSICS · Multi-part · Fermi University Physics · Electricity, Magnetism & Electromagnetism · Electric fields in matter · Electric fields in matter
The Boundary-Value Problem, Ch Linear dielectrics and the boundary-value problem with matter in it
Problem
Someone argues: 'A dielectric sphere always weakens the field inside it, because polarisation always opposes the applied field. Since εr=1 is the weakest possible dielectric response above vacuum, the interior field for εr=1 must still be somewhat below E0, tending towards zero as εr is reduced further.'
((a)) Using Ein=εr+23E0, evaluate Ein/E0 exactly at εr=1.
((b)) Say in one sentence why this value, and not zero, is the correct one, and identify the two separate limits of εr that must not be confused.