MCAT Physics Question 69: Answer and Explanation

Home > MCAT Test > MCAT physics practice tests

Test Information

Question: 69

9. Given an electric dipole, the electrical potential is zero:

  • A. only at the midpoint of the dipole axis.
  • B. anywhere on any perpendicular bisector of the dipole axis and at infinity.
  • C. anywhere on the dipole axis.
  • D. only for points at infinity.

Correct Answer: B

Explanation:

Potential is a scalar quantity. The total potential is the sum of the potentials of the positive and negative charges:

where r+ and r represent the distances from the positive and negative charge, respectively. The sum of these terms will be zero at any point where r+ = r. This will be at any point along the perpendicular bisector of the dipole axis, as well as at infinity.

Previous       Next