【简答题】A semicircular wire (radius R=20cm) is moving with speed v=3m/s in the plane it lays, the moving direction is perpendicular to the diameter line (dashed line in the figure). If there is a magnetic fie...
【简答题】A surveyor is using a magnetic compass 6.1 m below a power line in which there is a steady current of 100 A. (a) What is the magnetic field at the site of the compass due to the power line? (b) Will t...