A Level Computer Science OCR Practice Exam

Which type of storage is characterized by light being used to read marks and bumps?

1. Magnetic Storage

2. Solid State Storage

3. Optical Storage

4. RAM

The correct answer is: Optical Storage

Optical storage is characterized by the use of light to read marks and bumps on the surface of a disc. This type of storage relies on lasers to interpret the data encoded in the form of pits and lands on optical media such as CDs, DVDs, and Blu-ray discs. When a laser beam is directed onto the disc, the varying levels corresponding to the pits and bumps reflect the light differently, which is then translated into digital information. This type of storage is distinct from other forms. For instance, magnetic storage uses magnetism for reading and writing data, typically on devices like hard disk drives, which involve spinning disks and magnetic heads. Solid-state storage, such as SSDs, relies on flash memory and does not involve any moving parts or light but instead stores data in a series of memory cells. RAM is a type of volatile memory that provides quick access to data but also does not use light in its operations, instead relying on electrical charges to hold data temporarily while the computer is powered on. Each of these alternatives operates based on different principles, clearly setting optical storage apart as the option that uses light.