Answer: F = kq 1 q 2 /r 2.
- A F = kq<sub>1</sub>q<sub>2</sub>/r
- B F = kq<sub>1</sub>q<sub>2</sub>/r<sup>2</sup>
- C F = kq<sub>1</sub>q<sub>2</sub>*r<sup>2</sup>
- D F = k(q<sub>1</sub>+q<sub>2</sub>)/r<sup>2</sup>
Correct answer: B. F = kq<sub>1</sub>q<sub>2</sub>/r<sup>2</sup>
Explanation: F = kq<sub>1</sub>q<sub>2</sub>/r<sup>2</sup> where k = 9 x 10<sup>9</sup> N m<sup>2</sup>/C<sup>2.</sup> Force is proportional to product of charges and inversely to r<sup>2.</sup>
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.