Electric field lines are used to represent the field produced by a point charge. Which of the following is true about field lines?

Electric field lines are used to represent the field produced by a point charge. Which of the following is true about field lines?

• A. They begin on negative charges and end on positive charges.
• B. They begin on positive charges and end on negative charges.
• C. They form closed loops around charges.
• D. They indicate energy transported by the field.

Answer: (B)

Field lines show the direction a positive test charge would feel the field to move, so they originate from sources of positive charge and terminate on negative charges, which act as sinks. In a system with both positive and negative charges, the lines naturally flow from the positive to the negative, illustrating that the field points away from positive sources and toward negative charges. They do not form closed loops in electrostatics because there are sources and sinks at the charges, and lines must begin or end there rather than looping endlessly. Also, field lines visualize the direction of the electric field, not energy flow; energy transport in electromagnetic fields is described by the Poynting vector, not by the lines themselves.

Field lines show the direction a positive test charge would feel the field to move, so they originate from sources of positive charge and terminate on negative charges, which act as sinks. In a system with both positive and negative charges, the lines naturally flow from the positive to the negative, illustrating that the field points away from positive sources and toward negative charges. They do not form closed loops in electrostatics because there are sources and sinks at the charges, and lines must begin or end there rather than looping endlessly. Also, field lines visualize the direction of the electric field, not energy flow; energy transport in electromagnetic fields is described by the Poynting vector, not by the lines themselves.