What is a discharge tube used for?

A discharge tube is primarily used to investigate the effect of electricity through gases at low pressures. When an electric current is passed through the gas contained in the tube, it can emit light and other forms of radiation, revealing important information about the nature of the gas and the behavior of electrons within it. This experimental setup can demonstrate phenomena such as ionization and the properties of cathode rays.

Discharge tubes are instrumental in experiments that led to significant advancements in our understanding of atomic and molecular structures, including studies on gas discharge, the emission spectrum of gases, and the behavior of electrons in electric fields. These investigations form the foundation for various applications in fields such as plasma physics and neon lighting.

While other options may seem relevant, they do not accurately describe the main function of a discharge tube. For instance, measuring electric field strength typically requires different instrumentation, and while high voltages might be present in certain experiments concerning discharge tubes, the tube itself is not designed as a voltage generator. Similarly, storing electrical energy is not what a discharge tube is intended for; instead, it focuses on the interaction between electricity and gases.