The Rydberg constant is a fundamental physical constant that describes the wavelengths of spectral lines in hydrogen and other hydrogen-like atoms. It is named after the Swedish physicist Johannes Rydberg, who formulated a formula to predict these wavelengths. The constant is denoted by the symbol R_\infty and has a value of approximately 1.097 \times 10^7 \, \textm^-1 . This constant plays a crucial role in atomic physics and quantum mechanics, as it helps in understanding the energy levels of electrons in atoms. The Rydberg formula uses the Rydberg constant to calculate the wavelengths of light emitted or absorbed when electrons transition between energy levels, providing insights into atomic structure and behavior.