Scenario I: Two point charges +q and +2q are separated by a distance d in vacuum, giving a potential energy U_I.
Scenario II: The same charges are separated by a distance d⁄2 inside a material with relative permittivity ε_r = 4, giving a potential energy U_II.
What is the ratio U_II ⁄ U_I?
a) 2.0
b) 0.125
c) 0.50
d) 1.0