Ch. 3 IGCSE ICT

A Blu-ray disc should be used to store a high definition movie of two hours needing a storage capacity of 25 GB. Blu-ray discs have a larger storage capacity compared to DVDs, CDs, and hard disks. They can hold up to 25 GB (single-layer) or 50 GB (dual-layer) of data, making them ideal for storing large files such as high definition movies.

The correct answer is relatively expensive. Blu-ray disks are known to be more expensive compared to DVDs. This is because the technology used in Blu-ray disks, such as the blue laser, allows for higher storage capacity and better video and audio quality. However, this advanced technology comes at a higher cost, making Blu-ray disks relatively expensive compared to DVDs.

CD ROM should be used as CD RW is expensive .

The laser wavelength affects the storage capacity of a media because shorter wavelengths allow for more data to be packed into a given space. This is because shorter wavelengths have a higher frequency and can therefore encode more information per unit of space. Therefore, shorter wavelengths result in greater storage capacity.

The correct answer is "Direct" because magnetic disks allow direct access to data, meaning that any part of the disk can be accessed directly without having to read through all the preceding data. This is in contrast to serial access, where data is accessed sequentially in a linear fashion. Direct access is faster and more efficient for random access and retrieval of data from a magnetic disk.

Data transfer is fast .

Backing up refers to the process of creating copies of files and data from a main secondary storage device to a different medium. This is done as a precautionary measure in case there is a problem with the main storage device, such as data loss, corruption, or hardware failure. By regularly backing up files, individuals and organizations can ensure that their important data is safe and can be easily restored if needed.