Question: an alpha particle a he nucleus containing two protons and...
An alpha particle (a He nucleus, containing two protons and two neutrons and having a mass of 6.64×10−27kg) traveling horizontally at 35.6 km/s enters a uniform, vertical, 1.80 T magnetic field.
So, I converted the kg into g, km/s into m/s, but somehow the radius I got was .410 milimeter and not meters. I already have the answers I just need to know is how I got milimeters instead of meters. Please explain in detail, don't leave anyting out, thank you.