because excite of gaseous atoms emit photons .
If it's a *Crookes* tube you're asking about, it's a discharge tube because the applied electrical field causes ionization and a resulting discharge of energy in the form (mostly) of light, depending on the gas or gases in the tube.
Yes because it glows when it glows the tube expands to create space for it to glow
Johann Wilhelm Hittorf, a German physicist, is credited with discovering the gas discharge tube in the mid-19th century. His experiments with cathode rays in partially evacuated tubes laid the foundation for the development of early gas discharge tubes.
When the pressure is reduced in a discharge tube, the mean free path of the gas molecules increases. This allows the gas molecules to gain more energy and move freely, colliding with the charged particles in the discharge tube and facilitating the flow of electric charge. As a result, the gases become partially ionized, creating a conductive path for the electricity.
Here is a website that will help you out with Helium as well as other gasses that emit colours when in a glass tube with electricity running through at the related link.
greenish glow or fluorescence
At very low pressure in a discharge tube, there are fewer gas atoms present to ionize and produce light. This results in fewer collisions and less emission of visible light, causing the discharge tube to appear dark.
it will not glow
If it's a *Crookes* tube you're asking about, it's a discharge tube because the applied electrical field causes ionization and a resulting discharge of energy in the form (mostly) of light, depending on the gas or gases in the tube.
A glass tube filled with neon gas with an electrode at each end will glow red-orange when electricity flows through it.
Yes because it glows when it glows the tube expands to create space for it to glow
Peanut butter does not naturally glow in the dark. If it appears to glow, it may be due to certain additives or chemicals that have been added to it.
You get a tube and fill it with glowey stuff thers your answer
He is a scientist who modified and experimented with discharge tube
Very. It appears in many glow-in-the-dark watches.
Guess hehe
The electrons emitted from cathode hit the glass of the tube, causing it to fluoresce.