Computer Science for IGCSE & O level - Data Transmission (Section 5)
1
Which of the following statement(s) is/are true about the Transport Layer?
Trả lời
A
C
2
Which of the following are used for error detection?
Trả lời
A
B
3
What kind of error detection is used when data are sent back to the sender?
Trả lời
(C)
Echo check
4
Which error-detection technique typically involves the retransmission of data?
Trả lời
(D)
Automatic Repeat Request (ARQ)
5
Which term applies to a situation where two digits swap their positions in the process of data entry?
Trả lời
(B)
Transposition Error
6
Which of the following would be best suited for a two-way communication?
Trả lời
(C)
Full-duplex communication
7
In encryption, which of the following terms is used to describe the message before it is encrypted?
Trả lời
(B)
Plaintext
8
What is the first number in a node, which is calculated from all the numbers in the code, to ensure the errors in data entry?
Trả lời
(C)
Check digit
9
What does the term 'encryption' mean?
Trả lời
(A)
The process of converting data into an unreadable format.
10
What is the main security benefit of using a VPN?
Trả lời
(B)
It protects your internet traffic from eavesdropping and censorship.
11
Which of the following is a type of attack that attempts to make a network resource unavailable to its intended users?
Trả lời
(C)
Denial-of-service (DoS)
12
In packet switching, what information does the header include to make sure that the packets can be assembled in the correct order?
Trả lời
(C)
Sequence number.
13
Which of the following is a benefit of using a switch compared to a hub?
Trả lời
(C)
Switches forward traffic only to the intended recipient, increasing efficiency.
14
In packet switching, what are the advantages of using different routes?
Trả lời
B
C
15
Why are packets sometimes reordered when using packet switching?
Trả lời
(A)
Because each packet may take a different route.
16
What is the function of 'ARP' (Address Resolution Protocol)?
Trả lời
(B)
To resolve IP addresses to MAC addresses.
17
What is the main security risk associated with using symmetric encryption?
Trả lời
(A)
The same key is used for both encrypting and decrypting, which can make it difficult to share the key securely.
18
What are some of the main advantages of a wireless network (Wi-Fi)?
Trả lời
A
B
19
Which of the following is NOT a characteristic of full-duplex data transmission?
Trả lời
(C)
A single channel is used for transmission.
20
Which of the following statements is true regarding symmetric encryption?
Trả lời
(C)
It uses the same key for encryption and decryption.
21
Which of the following factors influence how data is transmitted?
Trả lời
A
B
C
22
In a network, what task does a router primarily perform?
Trả lời
(B)
Forwarding data packets.
23
Which of the following best describes the operation of an echo check?
Trả lời
(B)
The receiver sends a copy of the data back to the sender to verify it.
24
What is 'social engineering'?
Trả lời
(C)
The practice of manipulating people into revealing confidential information.
25
What kind of error could be detected by parity blocks?
Trả lời
(D)
Both single and burst errors and errors where one bit has changed
26
Which of the following is a function of the 'application layer' of the OSI model?
Trả lời
(C)
Providing network services to applications.
27
Which of the following best describes "automatic repeat request (ARQ)"?
Trả lời
(B)
A system for detecting and correcting errors by retransmitting data.
28
In the context of data transmission, what does the term "checksum" refer to?
Trả lời
(B)
A method of error detection.
29
What does the acronym ARQ stand for?
Trả lời
(B)
Automatic Repeat Request
30
What are the common methods for detecting errors in data transmission?
Trả lời
A
B
C
31
What is a 'MAC address' used for?
Trả lời
(A)
To identify a device on a network at the data link layer.
32
What does USB stand for?
Trả lời
(A)
Universal Serial Bus
33
What is the key difference between serial and parallel data transmission?
Trả lời
(A)
Serial transmits data one bit at a time, while parallel transmits several bits simultaneously.
34
When using asymmetric encryption, how is the sender's private key typically used?
Trả lời
(C)
To create a digital signature.
35
Which of the following are examples of network protocols?
Trả lời
A
B
C
D
36
What does 'VPN' stand for?
Trả lời
(A)
Virtual Private Network
37
What is 'spoofing' in a network context?
Trả lời
(B)
An attack where an attacker impersonates a legitimate entity.
38
What is the purpose of a public key in asymmetric encryption?
Trả lời
(B)
To encrypt messages only.
39
What is the primary function of the "header" in a data packet?
Trả lời
(B)
Provides information about the data, such as source and destination addresses.
40
What type of transmission is often used for connecting a computer to a printer via a USB connection?
Trả lời
(C)
Full-duplex
41
In the example of ISBN-13 algorithm where 978030640615X, what is the calculation algorithm is used?
Trả lời
(A)
Weighted sum and then divide by 10 to find remainder
42
Why are check digits used?
Trả lời
(C)
To detect errors, such as when data is entered incorrectly.
43
What is the primary benefit of breaking data into packets before transmission?
Trả lời
(C)
It allows data to be sent via a different route.
44
Which of the following protocols is often used to encrypt web traffic?
Trả lời
(C)
HTTPS
45
What is the term for the combination of hardware and software that translates signals from a computer into signals that can be transmitted over a phone line?
Trả lời
(C)
Modem
46
Which of the following is the correct name for a form of encryption that involves both the sender and the recipient use the same key to encrypt and decrypt?
Trả lời
(A)
Symmetric key encryption
47
Which of the following is an example of a "checksum"?
Trả lời
(B)
A hash value used to verify data integrity
48
What is the function of a 'checksum' in data transmission?
Trả lời
(B)
To detect errors in the data.
49
In asymmetric encryption, what happens if someone has your public key?
Trả lời
(B)
They can encrypt messages to you.
50
Which method is most suitable for long-distance communication?
