Computer Science for IGCSE & O level - Data Representation (Section 15)
1
What operation is equivalent to shifting a binary number three places to the right?
Απάντηση
(B)
Dividing by 8
2
What color does #0000FF represent in HTML?
Απάντηση
(C)
Blue
3
In HTML color codes, how many hexadecimal digits are used to represent each color (red, green, and blue)?
Απάντηση
(B)
2
4
Which is the value of the 8-bit two's complement representation of -1?
Απάντηση
(B)
11111111
5
How is a switch represented in a computer's binary system?
Απάντηση
(B)
Using the value 1 to represent the 'ON' state, and 0 for the 'OFF' state.
6
A music file is 5MB in size. How much space does it use if it is saved in the same format, and is double the duration?
Απάντηση
(C)
10MB
7
What is the minimum value that can be represented using a single byte?
Απάντηση
(A)
0
8
What does the acronym 'IP' stand for?
Απάντηση
(A)
Internet Protocol
9
Which factor does NOT directly affect the file size of an image?
Απάντηση
(D)
The camera's brand
10
What is the purpose of the MSB (Most Significant Bit) in a two's complement number?
Απάντηση
(B)
To indicate the sign (positive or negative) of the number.
11
What operation does a logical right shift perform on a binary number?
Απάντηση
(B)
Division by a power of 2.
12
Which of the following is a key advantage of Unicode over ASCII?
Απάντηση
(C)
It supports a much wider range of characters.
13
How is the concept of 'carry' relevant in the context of binary addition?
Απάντηση
(B)
It represents the overflow to the next bit position.
14
Which of the following accurately describes how HTML uses hexadecimal values for color?
Απάντηση
(A)
By using a 6-digit code where the digits determine the red, green and blue components.
15
What is the primary purpose of Unicode?
Απάντηση
(B)
To provide a more comprehensive character encoding standard.
16
What is the advantage of using hexadecimal in computer science?
Απάντηση
A
D
17
What are the potential benefits of applying data compression?
Απάντηση
A
B
18
What is the effect on an image's file size if you double both its width and height (and maintain the same color depth)?
Απάντηση
(D)
The file size is quadrupled.
19
What is the effect of increasing the color depth of a bitmap image?
Απάντηση
(B)
The image quality increases, and the file size increases.
20
What type of data is best compressed using Run Length Encoding (RLE)?
Απάντηση
(C)
A text file with repeating characters.
21
In the context of image file compression, what does the term 'color depth' refer to?
Απάντηση
(A)
The number of colors the image can display.
22
In digital audio, what does the term 'sampling' refer to?
Απάντηση
(B)
The measurement of the amplitude of a sound wave at regular time intervals.
23
Which statement is true concerning a higher sample rate?
Απάντηση
(A)
A higher sample rate will create larger file sizes, while potentially providing higher quality audio.
24
If an image is compressed using a lossy compression algorithm, what will happen?
Απάντηση
A
B
C
25
How many possible colors can be displayed using a 24-bit color system (RGB) ?
Απάντηση
(C)
16777216
26
Which image file format frequently utilizes lossy compression?
Απάντηση
(D)
JPEG
27
What type of values can be represented using a hexadecimal number?
Απάντηση
(D)
Colors and other data
28
What is the primary advantage of using Lossy compression?
Απάντηση
(B)
It creates smaller file sizes, making them easier to share.
29
What is the name given to half a byte of memory?
Απάντηση
(D)
A nibble
30
What is an advantage of representing data using hexadecimal notation compared to using decimal notation?
Απάντηση
(B)
It directly relates to binary, making it easier to convert.
31
How many different digits does the hexadecimal number system use?
Απάντηση
(D)
16
32
A photograph is taken using a digital camera. If the number of pixels is doubled in both horizontal and vertical directions, how does the file size change (assuming the color depth remains the same)?
Απάντηση
(C)
The file size quadruples.
33
What does the acronym 'RLE' stand for in the context of data compression?
Απάντηση
(B)
Run Length Encoding
34
Which compression technique is most suitable for compressing text files?
Απάντηση
(D)
Run-length encoding
35
Which statement is true about binary addition?
Απάντηση
(A)
1 + 1 = 10 (with a carry of 1)
36
What is the two's complement representation of the decimal number -4 using 4 bits?
Απάντηση
(D)
0100
37
What is the result of the binary subtraction: 1111 - 0011?
Απάντηση
(A)
1100
38
What does a left bit shift do to the binary number?
Απάντηση
(B)
Multiplies it by two
39
Which of the following is the result of applying two's complement to the binary number 01100101?
Απάντηση
(B)
10011011
40
What is the key characteristic of lossy compression?
Απάντηση
(A)
It discards some of the original data.
41
What does the term 'carry' mean in binary addition?
Απάντηση
(B)
To add 1 to the next most significant bit.
42
What is the role of a 'flag' in Run Length Encoding?
Απάντηση
(B)
To indicate that RLE compression is being used.
43
What is the result of the two's complement conversion of -7 using 4 bits?
Απάντηση
(D)
1000
44
What is the purpose of two's complement?
Απάντηση
(B)
To represent negative integers in binary.
45
What is the decimal value of the 8-bit two's complement number 11111110?
Απάντηση
(A)
-2
46
What does a higher bit depth in an audio recording generally provide?
Απάντηση
(C)
A greater dynamic range.
47
If a sound wave is sampled more frequently (higher sampling rate), what is the effect?
Απάντηση
A
C
48
What range of decimal numbers can an 8-bit unsigned integer represent?
Απάντηση
(B)
0 to 255
49
What are the consequences of reducing the sample rate of an audio file?
Απάντηση
A
B
50
What is a potential downside to a higher resolution in an image or video?
