Computer Science for IGCSE & O level - Data Representation (Section 5)
1
What is a fundamental difference between logical and arithmetic bit shifts?
Απάντηση
(B)
Arithmetic shifts preserve the sign of the number.
2
What are the properties of high-frequency waves?
Απάντηση
B
C
3
Which type of compression is generally preferred for archive files where data integrity is critical?
Απάντηση
(D)
Lossless
4
How many bits are in a byte?
Απάντηση
(C)
8
5
What is the decimal equivalent of the binary number 110101?
Απάντηση
(A)
53
6
What does a sample rate of 44.1 kHz mean in audio recording?
Απάντηση
(B)
44,100 samples are taken per second.
7
What is the result of shifting the binary number 1011 one position to the left?
Απάντηση
(B)
10110
8
What is the range of values that can be represented by a single hexadecimal digit?
Απάντηση
(C)
0-15
9
What is the hexadecimal representation of the decimal number 255?
Απάντηση
(A)
FF
10
What does a logical right shift do to a binary number?
Απάντηση
A
B
D
11
Which system uses letters A through F along with numbers 0-9?
Απάντηση
(C)
Hexadecimal
12
What is the two's complement representation of -1 in an 8-bit system?
Απάντηση
(B)
11111111
13
If an 8-bit register holds the value 00001010, and you perform a logical left shift, what is the resulting value?
Απάντηση
(A)
00010100
14
What is the decimal equivalent of the two's complement binary number 11111110 (assuming an 8-bit representation)?
Απάντηση
(A)
-2
15
What is the result of converting the hexadecimal number "2B" to decimal?
Απάντηση
(C)
42
16
What is a characteristic of a lossy compression algorithm?
Απάντηση
(C)
It reduces file size by discarding data.
17
In HTML color codes, the value 00 in the #RRGGBB format indicates:
Απάντηση
(B)
No intensity of that color component.
18
Which bit in two's complement representation indicates the sign of the number?
Απάντηση
(B)
The most significant bit (MSB)
19
What does a 'flag' do in RLE?
Απάντηση
(A)
It marks the beginning of a compressed sequence.
20
Which of the following is a common hexadecimal color code format?
Απάντηση
(A)
#RRGGBB
21
What is the relationship between the number of bits used to represent a sound sample (bit depth) and the quality of the sound?
Απάντηση
(C)
A higher bit depth results in a more accurate representation of the sound.
22
What characterizes lossless compression algorithms?
Απάντηση
(C)
They provide a perfect reconstruction of the original data.
23
What is the primary purpose of using error codes in a software system?
Απάντηση
(B)
To identify and categorize errors.
24
Which of the following is an example of a lossless compression technique?
Απάντηση
(C)
RLE
25
In an 8-bit system, what operation is needed to convert the two's complement representation of a negative number to its positive value?
Απάντηση
(B)
Invert the bits and add 1.
26
What is the main advantage of using Unicode over ASCII?
Απάντηση
(B)
Unicode can represent characters from all known writing systems.
27
What is the base of the hexadecimal number system?
Απάντηση
(D)
16
28
What are the two key concepts the JPEG reduction process is based on?
Απάντηση
(A)
Human eyes don't detect differences in colour shades quite as well, and they have differentness in image brightness.
29
What does the binary number 11111111 represent in an 8-bit system?
Απάντηση
(D)
All of the above, depending on context.
30
What is the main objective of data compression techniques?
Απάντηση
(B)
To reduce file size.
31
What is the relationship between file size and color depth?
Απάντηση
(B)
As color depth increases, file size increases.
32
If an image has a resolution of 1000x500 pixels and a color depth of 8 bits per pixel, what is the total number of bytes required to store the uncompressed image data?
Απάντηση
(A)
500000 bytes
33
Which of the following is an example of lossy compression?
Απάντηση
(C)
MP3
34
What is the decimal equivalent of the binary number 10111?
Απάντηση
(B)
22
35
Which number system is used to represent the on/off states of electronic components?
Απάντηση
(B)
Binary
36
What is the largest decimal value that can be represented by a single hexadecimal digit?
Απάντηση
(C)
15
37
What is the two's complement representation for -4 using a 4-bit system?
Απάντηση
(A)
1100
38
If an audio file has a bit depth of 8, what does this mean?
Απάντηση
(B)
Each audio sample is represented using 8 bits.
39
Which type of compression guarantees that the original data can be fully reconstructed?
Απάντηση
(C)
Lossless
40
Consider this scenario: A software developer is using a microphone to record surface sounds for their new game. Identify the essential aspects for recording the sound?
Απάντηση
A
C
41
What is the primary trade-off when using lossy compression?
Απάντηση
(C)
Smaller file size versus potential data loss.
42
What are characteristics of lossy compression techniques?
Απάντηση
(D)
All of the above.
43
In sound representation, the process of converting analog sound waves into digital data is known as:
Απάντηση
(B)
Sampling
44
Which type of compression would generally yield the smallest file size?
Απάντηση
(C)
Lossy
45
What is the result of the hexadecimal calculation 10 - 5?
Απάντηση
(A)
5
46
In computer science, what's the function of a computer's "switch" in relation to binary?
Απάντηση
(B)
To represent a bit value of either 0 or 1.
47
What process is used to convert from hexadecimal to decimal?
Απάντηση
(C)
Multiplying each hex digit by the base of 16 to its corresponding power and summing them.
48
What is the main advantage of using lossless compression?
Απάντηση
(B)
Guaranteed data integrity.
49
What is the range of decimal numbers that can be represented using a single byte (8 bits)?
Απάντηση
(B)
0-255
50
If you right-shift the binary number 1100, what is the result (assuming a logical shift)?
