An Electron Moving Perpendicular to a Uniform Magnetic Field of 3.2

Multiple Choice

An electron moving perpendicular to a uniform magnetic field of 3.2 × 10^-2 T moves in a circle of radius 0.40 cm.How fast is this electron moving? (e = 1.60 × 10^-19 C,m_electron = 9.11 × 10^-31kg)

A) 2.2 × 10⁷ m/s
B) 1.9 × 10⁷ m/s
C) 1.9 × 10⁶ m/s
D) 3.0 × 10⁷ m/s
E) 0.80 × 10⁷ m/s