Which equation expresses the electric force on a charge q in an electric field E?

Which equation expresses the electric force on a charge q in an electric field E?

• A. Fe = qE
• B. Fe = qV
• C. Fe = E/q
• D. E = F/q

Answer: (A)

The force on a charge in an electric field is proportional to both the charge and the field: F = qE. This shows that the force grows with larger charge and with a stronger field, and it points in the same direction as the field for a positive charge (and opposite for a negative charge). If you look at the other ideas, they describe different quantities. qV gives potential energy, not force. E/q would be the field per unit charge, not the force itself. E = F/q is a valid rearrangement that defines the field from force, but it doesn’t express the force directly in terms of q and E. So the direct, correct expression for the force is F = qE.

The force on a charge in an electric field is proportional to both the charge and the field: F = qE. This shows that the force grows with larger charge and with a stronger field, and it points in the same direction as the field for a positive charge (and opposite for a negative charge).

If you look at the other ideas, they describe different quantities. qV gives potential energy, not force. E/q would be the field per unit charge, not the force itself. E = F/q is a valid rearrangement that defines the field from force, but it doesn’t express the force directly in terms of q and E. So the direct, correct expression for the force is F = qE.