Before the advent of solid-state electronics, vacuum tubes were widely used in radios and other devices. A simple type of vacuum tube, known as a diode, consists of two cylindrical electrodes within a highly evacuated enclosure. One electrode, the cathode, is maintained at a high temperature and emits thermally excited electrons from its surface. The other electrode, called the anode, is maintained at a certain voltage above the cathode, so the ejected electrons accelerate toward the anode. Suppose the cathode has a radius of 0.620 mm, and that the coaxial cathode has a radius of 55.8mm. The potential difference between the anode and cathode is 370 V. If an electron leaves the cathode at rest, what will be its speed when it reaches the andoe?