An electric field is a physical field that surrounds electrically charged particles and exerts a force on other charged particles within the field. The strength and direction of the electric field at any point in space is determined by the magnitude and distribution of the charges that create the field. The electric field is a vector field, meaning that it has both magnitude and direction, and is typically represented by electric field lines that show the direction of the force that a positive test charge would experience if placed in the field. The SI unit of electric field is volts per meter (V/m).