Which of the following storage mediums relies purely on magnetic property manipulation to record digital data? MCQ with Answer and Explanation

Explanation:
Hard disks are magnetic storage devices that use magnetic media to store data. SSDs and pen drives use flash memory, and Blu-ray uses optical technology.

Explanation:
SRAM uses flip-flops to retain data as long as power is supplied, making it faster and eliminating the need for periodic refreshing cycles unlike DRAM.

Explanation:
DRAM stores data in capacitors, which lose charge over time; thus, it requires periodic refreshing (every few milliseconds) to retain data. SRAM is faster but more expensive.