Then as the electrons in the atoms fall back down, they emit electromagnetic radiation (light). The amount of light emitted at different wavelengths, called the emission spectrum, is shown for a discharge tube filled with hydrogen gas in Figure 12.6 below.
It would be plastic Becaus we can recreate things with plastic and other things that are recyclable. Since,we mostly cut down trees everyday for paper,not knowing that we are wasting natural resources, and destroying animal homes and food.
I think cathode should be silver or gold
you can use silver nitrate solution or mercury nitrate solution