Answer: one quarter.
- A one quarter
- B one half
- C double
- D four times
Correct answer: A. one quarter
Explanation: F ∝ 1/r², so doubling r reduces the force to one quarter.
Field lines always point from positive to negative charge, are denser where the field is stronger, and never cross; an isolated positive charge has lines radiating symmetrically outward, while a dipole's lines curve from the positive to the negative charge.
Concept context
Coulomb's law, electric field, potential, capacitors, Gauss's law.