Explanation: In the context of digital storage media, CDs (Compact Discs) and DVDs (Digital Versatile Discs) are both optical discs used to store digital data. However, they differ significantly in their storage capacities and technological capabilities.
A CD, introduced in the early 1980s, is a standard optical disc with a storage capacity of 700 MB. CDs are primarily used for storing audio, software, and data. They are made of a polycarbonate plastic substrate, a reflective layer, and a protective lacquer layer. The data is stored in the form of pits and lands on the disc's surface, which are read by a laser in the CD player.
On the other hand, DVDs were introduced in the mid-1990s as an improvement over CDs. DVDs have a much higher storage capacity, typically ranging from 4.7 GB for a single-layer disc to 17 GB for a dual-layer disc. This increased capacity is due to several technological advancements, including a smaller laser wavelength, a thinner protective layer, and a more efficient data encoding method. DVDs can store high-definition video, large software applications, and extensive data files, making them more versatile than CDs.
The storage capacity of DVDs is achieved through several key features:
1. **Smaller Laser Wavelength**: DVDs use a shorter wavelength laser (650 nm) compared to CDs (780 nm), allowing for more precise data storage.
2. **Thinner Protective Layer**: The protective layer on DVDs is thinner, allowing the laser to focus more accurately on the data layer.
3. **Data Encoding**: DVDs use a more efficient data encoding method, which allows for more data to be stored in the same physical space.
These advancements in technology have made DVDs a preferred choice for storing larger amounts of data, including high-definition video content, large software applications, and extensive data files. Therefore, DVDs hold more information than CDs, making option B the correct answer.
Understanding the differences between CDs and DVDs is crucial for comprehending the evolution of digital storage media and the technological advancements that have led to increased storage capacities. This knowledge is particularly relevant in the context of miscellaneous Indian General Knowledge (GK) as it pertains to technological advancements and their applications in everyday life.