At some instant an alpha particle (q=+2e) has the coordinates (3.0,0.0,0.0)(nm) and is moving along the positive x axis with 500 km/s while an electron at (0.0,4.0,0.0)(nm) is moving along the y axis with 1000 km/s.
a) the magnitude and direction of the total magnetic field at the origin.
b) the magnitude and direction of the magnetic force felt by the electron.