An alpha particle is moving at a speed of 5.0 x 10' m/s in a direction perpendicular to a uniform magnetic field of strength 0.040 T. The charge on an alpha particle is 3.2 x 10 19 C and its mass is 6.6 x 10727 kg. How long does it take the alpha particle (in microseconds) to make one complete revolution around its path? Use two significant digits. Note that lus = 1 x 10 's