A glass tube is filled with hydrogen gas. An electric current is passed through the tube, and the tube begins to glow a pinkish/purple color (this is how fluorescent bulbs and neon signs produce light). If you were to pass this pink light through a prism to separate the individual light frequencies, you would see that this pink light is composed of four distinct colors: violet, green, blue, and red. Notice the similarity between image (b) below and the Balmer Series lines from Question #3.

Question

Which is the best description of why this occurs?
The electrons within the hydrogen atoms gain energy from the current causing them to jump to higher energy orbitals. When they fall back to a lower energy orbital, they release a single photon. These photons have discrete energies equal to the difference in energy of the two orbitals.

Atoms contain continuous energy orbitals, meaning that the light the hydrogen atoms produce can be of any energy. Depending on the type of prism used, when the light reaches it, the prism will only allow specific light energies (frequencies) to pass through.

The light spectrum from any source contains all colors (frequencies) because Planck's constant (h) is so small.

Answer 1

The best description of why the light emitted by the hydrogen gas in the glass tube consists of distinct colors (violet, green, blue, and red) is:

The electrons within the hydrogen atoms gain energy from the current causing them to jump to higher energy orbitals. When they fall back to a lower energy orbital, they release a single photon. These photons have discrete energies equal to the difference in energy of the two orbitals.

This explanation accurately describes the process of electron excitation and the subsequent emission of photons with specific energies corresponding to the differences between quantized energy levels in hydrogen atoms. Each of these energies corresponds to a specific wavelength (or color) of light, which results in the observed distinct colors.