The electric field depicts the force exerted on other electrically charged objects by the electrically charged particle the field is surrounding. The electric field is a vector field with SI units of newtons per coulomb ($N C^{-1}$) or, equivalently, volts per metre ($V m^{-1}$ ). The SI base units of the electric field are $kg m s^{-3} A^{-1}$. The strength or magnitude of the field at a given point is defined as the force that would be exerted on a positive test charge of 1 coulomb placed at that point