PHY 2049 Study Guide - Midterm Guide: Vacuum Tube, Electric Field, Stationary Point
Document Summary
Study sections 23. 1 through 23. 3 of the textbook. Memorize the definition of potential (v = u/q). (note that alternative units of e are v/m. If the electric field is zero everywhere inside a region of space, the potential must also be zero in that region. If the electrical potential in a region is constant, the electric field must be zero everywhere in that region. A negative charge, if free, will tend to move. 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 essentially of two electrodes within a highly evacuated enclosure. One electrode, the cathode, is maintained at a high temperature and emits electrons from its surface. A potential difference of a few hundred volts is maintained between the cathode and the other electrode, known as the anode, with the anode at the higher potential.
