Magnetic Fields Example Problems

1. Two parallel wires 200 mm apart carry currents in the same direction of 5 A. Find the magnetic field between the wires 50 mm from one of them and 150 mm from the other.



2. A current of 0.5 A is passed through a solenoid wound with 20 turns/cm. A single loop of wire 10 mm in radius is bent around the middle of the solenoid. What should the current in this loop be in order for the magnetic field at its centre to cancel out the field of the solenoid there ?