Consider the setup shown in Fig. Determine the minimum amount of current required to keep the magnetic plate at a distance of 2.5 mm from the pole faces of an electromagnet having 1500 turns when the torque exerted by the spring at an effective radius of 20 cm is 20 N-m. Assume each pole face has a circular cross section. Consider the relative permeability of magnetic material and magnetic plate as infinity. Magnetic plate cm 1500 turns 3 cm air-gap 20 cm Spring