Two uniformly charged plates carrying opposite charges are separated by a distance of \(20 \mathrm{~mm}\). The magnitude of the charge density on each plate is \(3 \times 10^{-8} \mathrm{C} / \mathrm{m}^{2}\). An electron is launched with a speed of \(2.1 \times 10^{6} \mathrm{~m} / \mathrm{s}\) halfway between the two plates.

(a) How far does the electron travel before it hits one of the plates? 

(b) What speed does the electron attain before it hits a plate?