In a Mass Spectrometer, a Single-Charged Particle Has a Speed $1.00 \times 10 ^ { 6 } \mathrm {~m} / \mathrm { s }$

In a mass spectrometer, a single-charged particle has a speed of $1.00 \times 10 ^ { 6 } \mathrm {~m} / \mathrm { s }$ and enters a uniform magnetic field of $0.200 \mathrm {~T}$ at a right angle to the field. The radius of the resulting circular orbit is $20.75 \mathrm {~cm}$ . What is the mass of the particle? $\left( e = 1.60 \times 10 ^ { - 19 } \mathrm { C } \right)$

A) $1.67 \times 10 ^ { - 27 } \mathrm {~kg}$
B) $3.20 \times 10 ^ { - 27 } \mathrm {~kg}$
C) $9.11 \times 10 ^ { - 31 } \mathrm {~kg}$
D) $6.64 \times 10 ^ { - 27 } \mathrm {~kg}$