Flash Memory – Notes for Exams
✅ Definition:
Flash memory is a non-volatile memory that retains data even when power is turned off. It can be electrically erased and reprogrammed, making it suitable for portable devices.
📌 Important Points:
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Non-volatile: Retains data without power.
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Faster than HDDs but slower than RAM.
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Solid-state technology: No moving parts.
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Widely used in USB drives, SD cards, SSD, BIOS chips, etc.
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Developed from EEPROM (Electrically Erasable Programmable Read-Only Memory).
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Can be erased and written in blocks.
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Common in mobile phones, digital cameras, laptops, etc.
🧩 Types of Flash Memory:
| Type | Description | Example Devices |
|---|---|---|
| NAND | High density, faster write speed, cheaper | SSD, USB drives, memory cards |
| NOR | Fast read speed, reliable, used in code storage | BIOS, embedded systems |
🧪 Flash Memory vs EEPROM:
| Flash Memory | EEPROM |
|---|---|
| Erased in blocks/sectors | Erased byte by byte |
| Faster | Slower |
| Cheaper per bit | More expensive per bit |
📦 Examples of Flash Memory Devices:
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USB Flash Drive (Pen Drive)
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SSD (Solid State Drive)
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SD / microSD Card
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BIOS chip in motherboard
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Memory in smartphones
❓ Frequently Asked MCQs
✅ MCQs with Answers
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Flash memory is a type of:
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A) Volatile memory
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B) Optical memory
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✅ C) Non-volatile memory
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D) Cache memory
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Which of the following is based on flash memory?
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A) RAM
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✅ B) SSD
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C) DVD
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D) ROM
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What type of flash memory is used in SSDs?
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A) DRAM
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B) SRAM
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✅ C) NAND
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D) NOR
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Flash memory is derived from which technology?
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A) ROM
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✅ B) EEPROM
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C) RAM
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D) DRAM
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Which flash memory is commonly used in BIOS chips?
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A) NAND
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✅ B) NOR
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C) DRAM
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D) SDRAM
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Flash memory retains data:
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A) Until the computer is restarted
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✅ B) Even when power is turned off
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C) Only when connected to the internet
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D) Only during boot
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Which of the following is NOT a flash memory device?
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A) USB
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B) SSD
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✅ C) CD-ROM
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D) SD Card
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🔁 Previous Year Questions (PYQs)
SSC CHSL 2021:
Q: Flash memory is commonly used in which of the following devices?
Ans: USB drive
JKSSB 2023:
Q: Which type of memory is used in BIOS?
Ans: NOR Flash Memory
Bank PO 2020:
Q: What does flash memory mean?
Ans: Non-volatile memory that can be electronically erased and reprogrammed.
📎 Summary Chart
| Feature | Flash Memory |
|---|---|
| Volatility | Non-volatile |
| Speed | Faster than HDD |
| Used in | SSD, USB, BIOS |
| Based on | EEPROM |
| Types | NAND, NOR |