Computer Science for IGCSE & O level - Data Transmission (Section 6)
1
Which of these methods require a round-trip of data?
Trả lời
B
D
2
What kind of information are used to generate a check digit?
Trả lời
B
C
D
3
What is the purpose of a 'proxy server'?
Trả lời
(B)
To filter and cache network traffic.
4
Which of the following are examples of network security threats?
Trả lời
A
B
C
5
In the context of asymmetric encryption, who is the sender?
Trả lời
(A)
The follower
6
What is the function of 'segmentation' in data transmission?
Trả lời
(B)
To divide data into smaller, manageable units for transmission.
7
Which is used to identify the errors in data entry?
Trả lời
(B)
Check digits
8
How do echo checks identify errors?
Trả lời
(A)
By sending the data back to the sender.
9
Which of the following are examples of wired network technologies?
Trả lời
A
C
10
What is 'social engineering'?
Trả lời
(B)
The practice of manipulating people to gain information.
11
What distinguishes a full-duplex communication mode?
Trả lời
(B)
Data is sent in both directions simultaneously.
12
Which of the following is NOT a component of a typical packet header?
Trả lời
(C)
The payload.
13
What is the role of a private key in asymmetric encryption?
Trả lời
(C)
Decrypt data that was encrypted with the corresponding public key.
14
What are the common causes of data corruption during transmission?
Trả lời
A
B
C
15
Which of the following is the biggest disadvantage of using asymmetric encryption?
Trả lời
(A)
It is very complex and time-consuming
16
Which of the following is considered a 'layer 1' protocol in the OSI model?
Trả lời
(D)
The physical layer
17
What does the term 'firewall' primarily do in terms of network security?
Trả lời
(B)
Filters network traffic based on predefined rules.
18
What does full-duplex communication allow?
Trả lời
(B)
Data to be sent in both directions simultaneously.
19
What is the purpose of error-checking methods such as checksums and parity bits?
Trả lời
A
C
20
How does 'red-time streaming' relate to packet switching?
Trả lời
(A)
It increases the likelihood of packets getting reordered.
21
What are the key characteristics of serial data transmission?
Trả lời
(A)
Sends bits one at a time over a single channel.
22
What is the role of a sequence number in the packet header?
Trả lời
(B)
To reassemble packets in the correct order.
23
What type of data transmission is commonly used for longer distances?
Trả lời
(C)
Serial
24
Which type of data transmission is usually preferred for long distances?
Trả lời
(B)
Serial data transmission.
25
In the context of ISBN-13 calculation, which operation is used to calculate the check digit?
Trả lời
(B)
Modulo
26
What is the main advantage of asymmetric encryption over symmetric encryption?
Trả lời
(C)
Higher data security
27
What is an example of "plaintext"?
Trả lời
(D)
An email's body before encryption
28
What is the main limitation of using parity checks for error detection?
Trả lời
(A)
It can only detect single-bit errors.
29
What is a key advantage of using packet switching in a network?
Trả lời
(B)
More efficient use of network resources.
30
Which of the following are types of error detection techniques?
Trả lời
A
B
31
What are the benefits of using a USB system?
Trả lời
A
B
C
32
What is the function of the 'sequence number' in a packet's header?
Trả lời
(C)
To help reassemble packets in the correct order.
33
What is the role of the 'payload' in a data packet?
Trả lời
(B)
To contain the actual data being transmitted.
34
How does half-duplex data transmission work?
Trả lời
(B)
Data is sent in one direction at a time.
35
Which of the following uses an excluded value which is a result after blocks of data, the receiving computer also calculates the value from the blocks of data and compares the values?
Trả lời
(C)
Checksum
36
Which layer of the OSI model is responsible for formatting the data before transmission?
Trả lời
(A)
The Presentation Layer
37
What can cause data corruption during transmission?
Trả lời
A
C
38
Which type of transmission mode allows for sending data in only one direction?
Trả lời
(C)
Simplex
39
In the context of data security, what does "encryption" achieve?
Trả lời
(B)
Protects data by converting it into an unreadable format.
40
What is the primary purpose of the OSI model?
Trả lời
(B)
To provide a framework for understanding how networks operate.
41
Which of the following scenarios would be most likely to cause an error detectable by a parity check?
Trả lời
(A)
A single bit is flipped during transmission.
42
What is 'malware'?
Trả lời
(B)
Software designed to damage or disrupt a computer system.
43
What is the primary goal of using error detection methods in data transmission?
Trả lời
(C)
To identify and handle transmission errors.
44
What is a primary advantage of asymmetric encryption?
Trả lời
(B)
Simplified key exchange.
45
Which mode enables two-way communication at the same time?
Trả lời
(C)
Full-duplex
46
Which of the following is true about the security of symmetric encryption?
Trả lời
(A)
The key must be kept secret.
47
What type of error detection involves sending data twice and comparing the two instances?
Trả lời
(C)
Repetition
48
What are the possible causes of data corruption during data transmission?
Trả lời
A
B
C
49
What is the result of the ISBN-13 calculation for the number 978030640615X (where X represents the check digit)?
Trả lời
(C)
2
50
What is the role of 'authentication' in data security?
