An alpha particle is accelerated by two closely spaced, oppositely charged plates, as shown below.
An alpha particle moving between oppositely charged plates.
The alpha particle has a speed of m/s when it enters a slit in the positively charged plate. After traveling for 1 mm, it passes through a slit in the negatively charged plate. If the magnitude of the charge of each plate is , and if each plate has an area of , what will be the speed of the alpha particle when it reaches the negatively charged plate? (Note: the plate separation is small compared to the dimensions of the plates.)