"line of force." YourDictionary, n.d. Web. 15 January 2019. <https://www.yourdictionary.com/line-of-force>.
line of force. (n.d.). Retrieved January 15th, 2019, from https://www.yourdictionary.com/line-of-force
A line used to indicate the direction of a field, especially an electric or magnetic field, at various points in space. The tangent of a line of force at each point indicates the orientation of the field at that point. Arrows are usually used to indicate the direction of the force.