Solution Using Eq (4 5) we find
r  = m v / (qB)  = 9 ×10–31 kg × 3 × 107  m s–1 / ( 1 6 × 10–19 C × 6 × 10–4 T)
                      = 28 × 10–2 m = 28 cm
n = v / (2 pr) = 17×106 s–1   = 17×106  Hz   =17 MHz