An Electron Is Accelerated from Rest Through a Potential Difference $3.75 \mathrm { kV }$

An electron is accelerated from rest through a potential difference of $3.75 \mathrm { kV }$ . It enters a region where a uniform 4.0-mT magnetic field is perpendicular to the velocity of the electron. Calculate the radius of the path this electron will follow in the magnetic field. $\left( e = 1.60 \times 10 ^ { - 19 } \mathrm { C } , m _ { \text {electron } } = \right.$ $9.11 \times 10 ^ { - 31 } \mathrm {~kg}$ )

A) $2.2 \mathrm {~cm}$
B) $3.2 \mathrm {~cm}$
C) $4.2 \mathrm {~cm}$
D) $1.2 \mathrm {~cm}$
E) $5.2 \mathrm {~cm}$