Final answer:
The neon gas tube emits light with a greater number of spectral lines compared to the monochromatic red light produced by a helium-neon laser.
Step-by-step explanation:
When comparing the light from a glowing neon gas with the light in the beam of a helium-neon laser, we find that the light from the neon gas tube will exhibit a greater number of spectral lines. This is because a neon light tube emits light at various wavelengths due to the excitation of electrons in the gas atoms which then give off light as they return to a lower energy state. On the other hand, the light from a helium-neon laser tends to be very monochromatic, meaning it produces light at a single, pure wavelength, as a result of lasing action by the neon atoms which have been pumped to a metastable state by collisions with excited helium atoms. Helium-neon lasers often have a continuous output at the wavelength of 633 nm, appearing red, due to the most likely transition to the nearby state producing 1.96 eV photons. Therefore, the answer to the student's question is: a. neon gas tube.