ELECTRIC FIELD

Electric field-The space surrounding an electric charge or a group of charges in which another charge experiences a force is called an electric field.

➤If the force on the test charge is said to be the same at all points in a field both in magnitude and direction, then the field is said to be uniform.

➤If the force on the test charge varies from point to point in a field, then the field is said to be non-uniform.

Electric field can be considered as an electric property associated with each point in the space where a charge is present in any form. An electric field is also described as the electric force per unit charge.

The formula of electric field is given as;

                                                         E = F /Q

Unit of electric field is newton/coulomb

Electric field lines-

An electric field line is an imaginary line or curve drawn through a region of empty space so that its tangent at any point is in the direction of the electric field vector at that point

Properties of Electric Field Lines-

• Electric field lines always begin on a positive charge and end on a negative charge, so they do not form closed curves. They do not start or stop in mindspace
• The number of electric field lines leaving a positive charge or entering a negative charge is proportional to the magnitude of the charge.
• Electric field lines never intersect.
• In an uniform electric field, the field lines are straight, parallel and uniformly spaced.
• The electric field lines can never form closed loops, as line can never start and end on the same charge.
• These field lines always flow from higher potential to lower potential.
• If the electric field in a given region of space is zero, electric field lines do not exist.
• The tangent to a line at any point gives the direction of the electric field at the point. Also, this is the path on which a positive test charge will tend to move if free to do so.

Why don’t electric field lines intersect –

➤If the electric field lines intersect, then two tangents could be drawn at their point of intersection. Thus, the electric field intensity at the point will have two directions, which is absurd.