An electron having energy 10 eV is circulating in path having magnetic field 1.0 `xx` 10-4 Tesla, the speed of the electron will be
1.9 `xx` 106 m/s
1.9 `xx` 1012 m/s
3.8 `xx` 106 m/s
3.8 `xx` 1012 m/s
how?