CS Free MCQ Bank

[ Option A ]

Memory storage refers to devices or media used to store data and programs in a computer.

• Primary memory (Volatile) is directly accessible by the CPU and loses its data when the power is turned off, examples include RAM and cache. 
• Secondary memory (Non-Volatile) stores data permanently, such as hard disks, SSDs, and optical discs.
• Tertiary and offline storage is used for backups and large-scale data storage, including tape drives and external hard drives.

Storage units are used to measure the amount of data in a computer, starting from the smallest unit, a bit, to larger units like Byte, Kilobyte (KB), Megabyte (MB), Gigabyte (GB), and Terabyte (TB).

• Bit → Byte → KB → MB → GB → TB → PB → EB → ZB → YB. Trick “Bharat Ke Modi Gaye Taj Pe Ek Zaruri Yatra”.

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[ Option B ]

CSA stands for Computer Speed Addition. It refers to techniques used in computer arithmetic to perform addition faster, often by reducing the time required to handle carries during binary addition.
By designing circuits that can process sums and carries efficiently, computers can speed up arithmetic operations, which is critical in processors and digital systems.

[ Option B ]

[ Option C ]

To convert the hexadecimal number (1F.01B)₁₆ into its decimal equivalent, we first separate it into the integer part (1F) and the fractional part (.01B).

In integer part conversion, each digit is multiplied by 16 raised to the power of its position from right to left, starting with 0.
(1F)₁₆ = 1⋅16¹+F⋅16⁰ = 16+15 = 31
In fractional part conversion, each digit after the hexadecimal point is multiplied by 16 raised to a negative power corresponding to its position.
0⋅16⁻¹+1⋅16⁻²+B⋅16⁻³ = 0 + 0.00390625 + 0.002685546875 = 006591796875 ≈ 0.0065918
After combining integer and fractional parts, 31 + 0.0065918 = 31.0065918
 

[ Option A ]

To quickly convert a number from octal to hexadecimal, first convert the octal number into binary by replacing each octal digit with its 3-bit binary equivalent. Then, group the binary digits into 4-bit groups starting from the right. Finally, convert each 4-bit group into its hexadecimal equivalent. 
For example, to convert 356₈to hexadecimal:

• Convert each octal digit to 3-bit binary: 3 → 011, 5 → 101, 6 → 110 → 011101110₂
• Group into 4-bit sections from the right: 1110 1110₂
• Convert each group to hexadecimal: 1110 → E, 1110 → E → EE₁₆

So, 356₈ = EE₁₆.

[ Option D ]

The binary fraction (0.10101)₂ is converted to decimal by multiplying each digit with 2⁻ⁿ, where n is the position after the decimal point. Thus, it becomes 1×2⁻¹ + 0×2⁻² + 1×2⁻³ + 0×2⁻⁴ + 1×2⁻⁵. This equals 0.5 + 0 + 0.125 + 0 + 0.03125 = 0.65625. Therefore, the decimal equivalent of (0.10101)₂ is (0.65625)₁₀.

[ Option C ]

Binary Coded Decimal (BCD) is a method of representing each decimal digit (0 to 9) using a fixed number of binary bits. Each decimal digit is encoded using 4 bits, which is exactly half a byte and commonly called a nibble.

[ Option C ]

The hexadecimal number system is a base-16 positional numeral system used widely in computing and digital electronics. It uses 16 distinct symbols to represent values from 0 to 15:

• The first 10 symbols are the decimal digits 0 to 9.
• The next 6 symbols are the letters A to F, where value of A is 10 and F is 15.

[ Option D ]

[ Option B ]

[ Option B ]

In one’s complement representation, a negative number is obtained by inverting all the bits of its positive binary form. For (−8)₁₀, we first write +8 in 5-bit binary, which is (01000)₂. Now, by inverting each bit (all 0s become 1s and all 1s become 0s), we get (10111)₂. Hence, the one’s complement representation of (−8)₁₀ is (10111)₂.

[ Option D ]

BCD (Binary-Coded Decimal) represents decimal digits 0 to 9 using 4-bit binary codes.

🔶 BCD Valid Range: 0000 to 1001

🔶 1011 = 11 (which is not a valid decimal digit in BCD)

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[ Option A ]