How is data recorded on optical storage devices?

Data is recorded on optical storage devices by utilizing laser technology to create tiny pits on the disc's surface. These pits and the flat areas between them represent the binary data (1s and 0s) that computers use to process information. When the disc is played back, a laser reads these variations in height (pits versus flat areas), allowing the device to interpret the stored data.

This method of data recording is characteristic of optical storage media such as CDs, DVDs, and Blu-ray discs, which rely on the physical structure of the disc surface to encode information. Each pit corresponds to a specific data value, and the precision of the laser ensures accurate reading of the data.

Alternative methods mentioned in the other options involve different physical principles altogether. For instance, magnetic fields are used in magnetic storage devices like hard drives, while chemical reactions are relevant in certain types of data storage like photochromic or chemical-based media. Electrical signals are typically associated with solid-state storage, such as flash memory. Therefore, the technique of creating pits using laser technology is what distinctly identifies how data is recorded on optical storage devices.