MCAT Physics Question 63: Answer and Explanation

Home > MCAT Test > MCAT physics practice tests

Test Information

Question: 63

3. Question below refers to the figure below, in which F represents the electrostatic force exerted on charged particle S by charged particle R.

Assume the direction of F is the same direction as the electric field between R and S. If an electron were placed midway between R and S, the resultant electric force on the electron would be:

  • A. toward R.
  • B. toward S.
  • C. upward in the plane of the page.
  • D. downward in the plane of the page.

Correct Answer: B

Explanation:

An electric field's direction at a given point is defined as the direction of the force that would be exerted on a positive test charge in that position. Because electrons are negatively charged particles, they will therefore feel a force in the opposite direction of the electric field's vector. In this case, because the force points to the left (toward R), an electron will feel a force pointing to the right (toward S) if E is in the same direction as F.

Previous       Next