Computer Science for IGCSE & O level - Data Representation (Section 4)

  • 1
    Which component of a sound wave is associated with its pitch?
    Απάντηση
    (C)
    Frequency
  • 2
    What is the primary aim of using lossy compression?
    Απάντηση
    (B)
    Reducing file size.
  • 3
    What is the maximum value of a single hexadecimal digit?
    Απάντηση
    (C)
    15
  • 4
    What does the term 'MSB' stand for in computer science?
    Απάντηση
    (B)
    Most Significant Bit
  • 5
    What is a common use case for hexadecimal notation in computer graphics?
    Απάντηση
    (A)
    Specifying colors.
  • 6
    What best explains how the resolution affects image quality?
    Απάντηση
    (D)
    A higher resolution generally leads to a higher quality image.
  • 7
    What is the main advantage of two's complement for representing integers?
    Απάντηση
    (B)
    It simplifies arithmetic operations.
  • 8
    What is the result of shifting the binary number 1010 two places to the left?
    Απάντηση
    (B)
    1000
  • 9
    Which of the following are true about two's complement?
    Απάντηση
    A
    B
    C
  • 10
    What is the key characteristic of a lossy compression algorithm?
    Απάντηση
    (B)
    It discards some data to reduce file size.
  • 11
    What does higher bit depth in audio signify?
    Απάντηση
    A
    B
  • 12
    What happens when a number is left-shifted in an 8-bit register and the MSB is a 1?
    Απάντηση
    (D)
    The value might be incorrect due to overflow.
  • 13
    What is the main advantage of using lossy compression over lossless compression?
    Απάντηση
    (B)
    Smaller file sizes
  • 14
    What value is represented by the HTML color code #FFFFFF?
    Απάντηση
    (D)
    White
  • 15
    If the two's complement representation of a signed 8-bit integer is 10000000, what is its decimal equivalent?
    Απάντηση
    (C)
    -128
  • 16
    How many bits does a byte typically contain?
    Απάντηση
    (B)
    8
  • 17
    What is the hexadecimal value for the decimal number 12?
    Απάντηση
    (C)
    C
  • 18
    What are the common uses for RLE compression?
    Απάντηση
    A
    B
    D
  • 19
    What does the term 'channel' represent in audio recording, particularly in stereo sound?
    Απάντηση
    (C)
    A separate stream of audio information (e.g., left or right).
  • 20
    What does the amplitude of a sound wave represent?
    Απάντηση
    (C)
    The loudness or intensity of the sound.
  • 21
    What does the sampling rate of a sound refer to?
    Απάντηση
    (B)
    The number of times the sound wave is measured per second.
  • 22
    What is the smallest unit of memory in a computer?
    Απάντηση
    (B)
    Bit
  • 23
    If you have the hexadecimal value 7F, what is its decimal equivalent?
    Απάντηση
    (A)
    127
  • 24
    What is the decimal equivalent of the hexadecimal number 2A?
    Απάντηση
    (C)
    40
  • 25
    What are the common uses of Run-Length Encoding (RLE)?
    Απάντηση
    A
    B
  • 26
    If a camera takes a photograph, what type of file is produced?
    Απάντηση
    (B)
    JPEG
  • 27
    What are the steps involved in converting a decimal number to binary using the method of repeated division?
    Απάντηση
    (A)
    Repeatedly divide the decimal number by 2, and the remainders, when read in reverse order, are the binary equivalent.
  • 28
    Which of the following affects the file size of a bitmap image?
    Απάντηση
    A
    B
  • 29
    What is the term for the number of bits used to represent each color component (red, green, blue) in a digital image?
    Απάντηση
    (B)
    Bit depth
  • 30
    What does the term 'colour depth' refer to in the context of bitmap images?
    Απάντηση
    (B)
    The number of colours that each pixel can represent.
  • 31
    Why is hexadecimal commonly used when representing color values, such as in HTML or CSS?
    Απάντηση
    (B)
    Because it provides a simple, easily understood representation of color components.
  • 32
    Which compression method is used to reduce the size of data while maintaining its original form?
    Απάντηση
    (B)
    Lossless
  • 33
    Which of the following statements are true regarding bit shifting?
    Απάντηση
    A
    B
    C
  • 34
    What is a key advantage of using lossy compression algorithms?
    Απάντηση
    (C)
    Significantly smaller file sizes.
  • 35
    In hexadecimal, how many binary digits does a single digit represent?
    Απάντηση
    (D)
    4
  • 36
    What is the main advantage of using hexadecimal in place of binary?
    Απάντηση
    (B)
    Hexadecimal is shorter and easier for humans to read.
  • 37
    When converting binary numbers to hexadecimal values, how many binary digits are represented by each hex digit?
    Απάντηση
    (D)
    4
  • 38
    If the binary number 1010 is shifted right by one position, what is the result (assuming a logical right shift)?
    Απάντηση
    (C)
    0100
  • 39
    What decimal value corresponds to the hexadecimal digit 'D'?
    Απάντηση
    (D)
    13
  • 40
    What is the main characteristic of a lossless compression algorithm?
    Απάντηση
    (A)
    It guarantees the complete reconstruction of the original data.
  • 41
    What is the result of the binary addition 1111 + 0001?
    Απάντηση
    (A)
    10000
  • 42
    What is the hexadecimal equivalent of the decimal number 15?
    Απάντηση
    (C)
    F
  • 43
    What happens when a bit is shifted off the end of an 8-bit register during a left shift operation?
    Απάντηση
    (A)
    The bit is lost.
  • 44
    How many different values can be represented with a 4-bit binary number?
    Απάντηση
    (C)
    16
  • 45
    Which of the following are advantages of the hexadecimal system?
    Απάντηση
    A
    B
    C
  • 46
    Which character set is most commonly used for encoding text in modern computers?
    Απάντηση
    (B)
    Unicode
  • 47
    In the context of computers, what does the term 'denary' most closely relate to?
    Απάντηση
    (B)
    Decimal numbers
  • 48
    Convert the decimal number 42 to hexadecimal.
    Απάντηση
    (A)
    2A
  • 49
    What is the purpose of using run-length encoding (RLE)?
    Απάντηση
    (B)
    To compress data by replacing repeated sequences with a shorter representation.
  • 50
    What is the main benefit of data compression?
    Απάντηση
    A
    D