Electric field lines

When we talk about the basic concepts of electric field lines, they originate from bodies that contain electrical charges. They are fine lines or, to be precise, visualized lines that can trace the line of action and the force generated in any electrical field. 

A field line is always drawn tangentially from any point in the field. Hence, if you try to trace down the direction of the electrostatic force at any point in the electric field, all you need is to draw a tangent to get the force vector.

The second thing that electric field lines denote is the density of the force. If you see electric field lines and the distance between the two electric field lines, you can easily illustrate the force in the specific area—the closer the electric field lines, the stronger the electric field.

Moreover, the electric field lines are representations of the electrostatic forces. One must remember that these lines are imaginary and can not be seen in real life.

Properties of electric field lines

Electric field lines are imaginary lines that can help trace electric field forces with specific properties. Some of their properties are:

• Field lines never intersect each other: When we talk about electric field lines, they will never cut each other. If two electric field lines intersect each other, it means that there are two tangents at that point. This implies that there are two electric field directions at that point, which is impossible.
• The field lines are perpendicular and rise from the surface of the charge. If a rectangular or square body possesses the charge, all you need is to trace the electric field lines directed at a 90-degree angle from the surface. 
• The electric field lines can denote the magnitude of the charge or the amount of charge in a specific area. The more the electric field lines in one particular area, the greater the charge. With the increase in charge, the force at that area also increases. If you place a body in the electric field lines with greater density, the force at that area will increase.
• Electric field lines will always start from a positive point and end at a negative point. If anyone wants to test the direction of the electric field lines, they can always start from the positive side.
• Only a single charge must be used either to start a field line or to end it. If multiple charges are used, tracing the electrical field lines becomes complex.

Electrical field and the concept of attraction and repulsion

Electric field lines can depict the attraction and repulsion caused by a charge. These lines are the most extraordinary way to visualize electric fields. One can gauge the attraction between two oppositely-charged bodies and measure the repulsion between two bodies with similar charges. 

If you want to visualize electric field lines, there are specific rules to imagine them.

• The field lines must begin at a positive charge and end at a negative point. If there are two bodies with like heads, the electric field lines will oppose each other.
• When the electric field lines are closer to each other, then the force becomes stronger. Hence, using Coulomb’s law, you can get the intensity of the force at a particular point. When the pressure is more potent, the electric field lines are closed.
• The number of field lines ultimately depends on the charge. The greater the charge, the more field lines are seen. 
• As mentioned earlier, you will never see two electric field lines intersecting each other.
• The electric field lines and electric field are tangent to the point where they pass.

Concept of equipotential lines

Equipotential lines are the field lines that have the same potential. These lines are always perpendicular to the electric field lines. Moreover, no network is required to move a charge through a potential line.

Equipotential lines change the direction according to the shape of the body from where the charge is being emitted out. These lines are also seen in dipoles. The origination of these lines is the same as that of the electric field, only in the perpendicular direction. The middle point of such an electric plane will always have zero potential. 

Properties of equipotential surfaces

1. The electric field is always perpendicular to the equipotential surface.
2. Equipotential field lines can never intersect, the same as electric field lines.
3. The equipotential surfaces should be in the plane with the x-axis to maintain a uniform electric field.
4. The direction of an equipotential surface will always be from high potential to lower potential.
5. When we talk about an isolated charge, the equipotential surface will always be spherical.
6. The space between two different equipotential surfaces helps in identifying whether the field is strong or weak.