What is an optical disk?

An optical disk is indeed an electronic data storage device that is written and read using a laser. This technology allows for the storage of large amounts of data in a compact form factor, making it useful for distributing software, movies, music, and other types of media. Optical disks—such as CDs, DVDs, and Blu-ray discs—utilize pits and lands on the disk's surface that represent data. A laser in the disc drive detects these changes in light reflection, allowing the data to be accessed and retrieved.

In contrast, the other options refer to different components or concepts that do not align with the characteristics of optical disks. The physical part of a circuit board does not entail data storage. A measurement unit related to computer speed pertains to performance metrics rather than data storage types. Lastly, a programming language for microchips relates to software development for hardware rather than data storage solutions. Thus, the accurate definition of an optical disk is that it is a data storage medium utilizing laser technology for writing and reading data.