Currents of moving particles produce magnetic fields. A magnetic field vectorB determines the type of forces that the field exerts on a conductor carrying a current. If a conductor of length l carrying the current I is at an angle α with B, a total force F with the magnitude F=Iblsinα acts on it. The direction of the force F coincides with the directions of the current and the field B in accordance with the right-hand rule. Magnetic field lines can serve as a graphic representation of the magnetic field. Note that the magnetic field lines passing through any given point are tangent to the magnetic field vector B at that point. The direction of the magnetic field on the axes of a circular loop runs alongside the axes. In the center of the loop with radius R that carries a current I, the magnetic field equals to B=μ_{0}I/2R, where μ_{0}=4π*10^{-7} N/A^{2} is a magnetic constant. The magnetic field along the axes of the circular loop behaves as a complex function of x. When the distance is considerably greater than the radius of the loop, the field magnitude decreases by approximately l/x^{3}.