Computer Science/IT MCQs
Topic Notes: Computer Science/IT
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
181
In hexadecimal, what decimal value does the letter 'A' represent?
Answer:
10
In the hexadecimal system, the symbols A, B, C, D, E, and F are used to represent the decimal values 10, 11, 12, 13, 14, and 15, respectively.
182
The number (19)₁₀ is a value in which number system?
Answer:
Decimal
The subscript '10' explicitly denotes that this is a base-10 or decimal number.
183
Performing subtraction using the two's complement method involves:
Answer:
Finding the two's complement of the subtrahend and adding it to the minuend
The operation A - B is equivalent to A + (-B). The two's complement is used to find the representation of -B, allowing the subtraction to be carried out by an adder circuit.
184
What is the decimal equivalent of the binary number (1011)₂?
Answer:
11
(1 \* 2³) + (0 \* 2²) + (1 \* 2¹) + (1 \* 2⁰) = 8 + 0 + 2 + 1 = 11.
185
How does UTF-8 handle code points larger than 127 (the ASCII range)?
Answer:
It uses a sequence of two to four bytes, where the first byte indicates how many bytes are in the sequence
This multi-byte scheme is the core of how UTF-8 works. Special bit patterns in the first byte tell the parser how many subsequent bytes are part of the same character.
186
How is the decimal number 13 represented in binary?
Answer:
(1101)₂
13 can be broken down into powers of 2: 8 + 4 + 0 + 1, which corresponds to (1 \* 2³) + (1 \* 2²) + (0 \* 2¹) + (1 \* 2⁰), or 1101 in binary.
187
The two's complement representation is commonly used to:
Answer:
Represent negative integers
Two's complement is a mathematical operation on binary numbers that allows subtraction to be performed using addition, and it provides a standard way to represent negative numbers in computer systems.
188
Which number system is used by computers at the most fundamental level?
Answer:
Binary (Base-2)
Computers are built on electronic circuits that have two states: on or off. The binary system, with its two digits (0 and 1), is a natural way to represent these two states.
189
What is the main purpose of file permissions in an operating system?
Answer:
To control access and protect files from unauthorized changes or viewing.
File permissions are a key component of system security.
190
The number '5' as a character has a different ASCII value than the number 5 as a numerical value. The ASCII value for the character '5' is:
Answer:
53
In ASCII, the characters '0' through '9' are represented by the decimal values 48 through 57. Therefore, the character '5' is represented by 48 + 5 = 53.