Electric field

An electric Field is the region around a charge where another charge experiences an electric force. Electric field describes how an electric charge influences the surrounding space.

Electric Field Strength

The electric field strength at a point is defined as the electric force experienced per unit positive test charge placed at that point. $\boxed{\vec E=\frac{\vec F}{q_0}}$ where:

• $\vec E$ = electric field
• $\vec F$ = electric force on the test charge
• $q_0$ = positive test charge

Electric Field Lines

Electric field lines are imaginary lines used to visualize the direction and strength of an electric field.

Electric field lines ----

• Originate from positive charges and terminate on negative charges (or extend to/from infinity).
• The tangent to a field line gives the direction of $\vec E$.
• Closer field lines → stronger electric field.
• Farther apart field lines → weaker electric field.
• Two electric field lines never intersect, because the electric field at a point has only one definite direction.
• Field lines are perpendicular to the surface of a conductor in electrostatic equilibrium.