Answer
$T = 1.63\times 10^{-11}~s$
Work Step by Step
We can write an expression for the radius according to Chapter 28:
$r = \frac{mv}{\vert q \vert B}$
We can find the period $T$:
$T = \frac{2\pi~r}{v}$
$T = \frac{(2\pi)~(\frac{mv}{\vert q \vert B})}{v}$
$T = \frac{2\pi~m}{\vert q \vert B}$
$T = \frac{(2\pi)(9.109\times 10^{-31}~kg)}{(1.6\times 10^{-19}~C)(2.20~T)}$
$T = 1.63\times 10^{-11}~s$
