Answer: -8 10 -7 C.
- A +8 × 10<sup>-7</sup> C
- B -8 × 10<sup>-7</sup> C
- C +5 × 10<sup>-7</sup> C
- D -5 × 10<sup>-7</sup> C
Correct answer: B. -8 × 10<sup>-7</sup> C
Explanation: Each electron has charge -1.6 × 10<sup>-19</sup> C. Therefore q = -5 × 10<sup>12</sup> × 1.6 × 10<sup>-19</sup> = -8 × 10<sup>-7</sup> C.
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.