How does a hollow cathode lamp work?
A. A hollow cathode lamp is a “glow discharge lamp”. It works by having a potential difference between two points (anode +ve and a cathode -ve) and an inert gas between them at a particular pressure. The inner lining of the cathode is made from the desired element and this element is struck by ions. The ions cause atoms of the element to be removed from the surface. This is called sputtering.
