1. The problem statement, all variables and given/known data A telephone cable at a place has 4 long straight horizontal wires carrying a current of 1 ampere in the same direction east to west. The earth's magnetic field at the place is .39G, the angle of dip is 35°, and the magnetic declination is nearly zero. What are the resultant magnetic fields (magnitude and direction) at points 4cm below the cable? 2. Relevant equations μI/2∏r 3. The attempt at a solution Magnitude of the field due to the current carrying wires is 2x10-5T Components of the earth’s magnetic fields – Along the horizontal is BHcos35° = 3.19x10-5T Along the vertical is BVsin35° = 2.24x10-5T According to the right hand rule the magnetic field above the wires should be going into the plane and below should be coming out. I can’t ‘visualise’ the directions of the Earth's magnetic field so I can’t go any further. I have numerous questions like this one but I can never see the direction of the earth’s field when it has different angles of dip.