posted by Edmound .
A cosmic-ray proton in interstellar space has an energy of 11.0 MeV and executes a circular orbit having a radius equal to that of Mars revolving around the Sun (2.28 1011 m). What is the magnetic field in that region of space?
KE=mv²/2 => v=sqrt(2KE/m) =
=1.67•10⁻²⁷•4.6•10⁷/1.6•10⁻¹⁹•2.28•10¹¹ =2.1•10⁻¹² T