# Which, if any, of the following statements about electric field lines is/are true?

Which, if any, of the following statements about electric field lines is/are true?

• The electric field is always perpendicular to the surface outside of a conductor. - TRUE
• It is not possible for the electric field to ever be zero. - FALSE
• It is possible for two electric field lines to cross each other. - FALSE
• If an electron were placed on an electric field line, it would move in a direction perpendicular to the field. - NOT SURE
• If a proton were placed on an electric field line, it would move in a direction anti-parallel to the field. - NOT SURE
• If an electron and a positron were in the presence of a very strong electric field, they would move away from each other. - NOT SURE
• Electric field lines originate on positive charge and terminate on negative charge. - TRUE

I do not completely understand the movement of particles through an electric field. How to electrons and positrons move? What are the answers to the questions I'm not sure about?

"If an electron were placed on an electric field line, it would move in a direction perpendicular to the field."

Have you worked with electrostatics before? Do you know conceptually what happens to an electron when it's being subject to an electric field? If electric forces are hard for you to visualize try and make a similar analogy to magnets

"If a proton were placed on an electric field line, it would move in a direction anti-parallel to the field."

Same reasoning as what I said above. Again, think of them as magnets if it helps you visualize it better.

The last one you have to think about the forces acting on the particles. In this case it's a 'really strong electric field'. I would assume that any force from this field would outweigh any force between the two particles.

You are aware of how the electric field is defined - use it to determine the motion of a charged particle in a field. For example, a negatively charged particle like an electron will move to a higher potential, i.e. a direction opposite (anti parallel) to the field lines.

SammyS
Staff Emeritus