Electrons enter a region of perpendicular electric and magnetic fields (similar to Example 27. 5). The region occupied by the fields is \(40.0 \mathrm{~mm}\) long in the \(x\) direction, where \(x\) is taken to be the original direction of motion. After passing through this region, the electrons then travel an additional \(300 \mathrm{~mm}\) in the \(x\) direction before hitting a phosphorescent screen that lights up where the electrons strike it. The electrons pass undeflected through the region of perpendicular fields when \(E=2.0 \times 10^{3} \mathrm{~N} / \mathrm{C}\) and \(B=1.2 \times 10^{-3} \mathrm{~T}\).

(a) Determine the speed of the undeflected electrons.

(b) If the magnetic field is turned off but the electric field is left on, by what distance have the electrons been deflected when they reach the phosphorescent screen?