A spectrum discharge tube is a device used in laboratory settings to study the spectrum of light emitted by various gases when they are electrically excited. The tube typically contains a low-pressure gas, such as hydrogen, neon, or mercury, which emits light when a high voltage is applied across the gas. This causes the atoms or molecules in the gas to become excited, and as they return to lower energy states, they release light at characteristic wavelengths.
Key Features of a Spectrum Discharge Tube:
Electrode: The tube has electrodes at each end to apply an electrical current to the gas inside.
Gas: The gas inside the tube is often chosen for its unique spectral lines. Common gases include hydrogen, neon, argon, mercury, and others.
Spectral Lines: The light emitted by the gas passes through a prism or diffraction grating, creating a spectrum. The spectrum is characteristic of the elements in the gas.
Application: Spectrum discharge tubes are used to study the atomic structure of elements, help understand quantum mechanics, and serve as educational tools for demonstrating the properties of light and atomic transitions.
Types of Spectrum Discharge Tubes:
Hydrogen Spectrum Tube: Often used in the study of the hydrogen emission spectrum, which consists of specific visible lines (like the Balmer series).
Neon Spectrum Tube: Produces a bright red-orange light and is commonly used in neon signs.
Mercury Spectrum Tube: Used to produce a series of spectral lines, particularly in the ultraviolet and visible regions.