Why is Neon Gas Transparent in a Glass Tube but Glows in a Neon Discharge Tube?

Why is neon gas transparent in a glass tube?

Why doesn't the neon in the tube absorb the orange and red wavelength?

Explanation:

Neon gas is transparent in a glass tube because it does not emit light as it does in a neon discharge tube. Why doesn't the neon in the tube absorb the orange and red wavelengths?

Neon gas is transparent in a glass tube because it does not emit light as it does in a neon discharge tube. The lack of absorption of orange and red wavelengths by the neon gas in the glass tube can be explained by the absence of strong absorption lines in the neon spectrum at those specific wavelengths.

The phenomenon you describe can be explained by the difference between emission and absorption spectra in neon gas. In a neon discharge tube, a high voltage is applied, causing the neon atoms to become excited and emit light. This emission occurs when the excited neon atoms transition from higher energy levels to lower energy levels, releasing photons of specific wavelengths. The emission spectrum of neon includes bright reddish-orange wavelengths, which are characteristic of the excited state transitions in neon atoms.

On the other hand, a glass tube filled with neon appears transparent because it does not emit light as a neon discharge tube does. In this case, the neon gas is not excited, and therefore, it does not emit photons. However, that does not necessarily mean it cannot absorb light.

The transparency of the glass tube filled with neon can be attributed to the absence of absorption lines in the visible spectrum for neon gas at normal conditions. Neon gas does not have strong absorption lines in the orange and red wavelengths, which are emitted by the excited neon atoms. As a result, when light containing these wavelengths passes through the neon-filled glass tube, it does not encounter significant absorption by the neon atoms.

Therefore, the lack of absorption of orange and red wavelengths by the neon gas in the glass tube can be explained by the absence of strong absorption lines in the neon spectrum at those specific wavelengths.