The force between two point charges placed in air is F. If air is replaced by a medium of relative permittivity εr, the force is reduced to
Correct answer: C. F/εr
- A. εrF
- B. εr/F
- C. F/εr
- D. Fεr
Explanation
The force between charges in a dielectric medium is reduced by a factor equal to the relative permittivity (or dielectric constant) of that medium. Therefore, the new force F' = F_air / εr.
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Electrostatics describes forces between charges through Coulomb's law, electric fields and field intensity, then uses electric potential to measure energy per unit charge. Capacitors store charge and electrical energy, with capacitance depending on geometry and dielectric material, not simply on the amount of charge present.
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