Computer Science for IGCSE & O level - Data Transmission (Section 5)
1
Which of the following statement(s) is/are true about the Transport Layer?
Răspuns
A
C
2
Which of the following are used for error detection?
Răspuns
A
B
3
What kind of error detection is used when data are sent back to the sender?
Răspuns
(C)
Echo check
4
Which error-detection technique typically involves the retransmission of data?
Răspuns
(D)
Automatic Repeat Request (ARQ)
5
Which term applies to a situation where two digits swap their positions in the process of data entry?
Răspuns
(B)
Transposition Error
6
Which of the following would be best suited for a two-way communication?
Răspuns
(C)
Full-duplex communication
7
In encryption, which of the following terms is used to describe the message before it is encrypted?
Răspuns
(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?
Răspuns
(C)
Check digit
9
What does the term 'encryption' mean?
Răspuns
(A)
The process of converting data into an unreadable format.
10
What is the main security benefit of using a VPN?
Răspuns
(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?
Răspuns
(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?
Răspuns
(C)
Sequence number.
13
Which of the following is a benefit of using a switch compared to a hub?
Răspuns
(C)
Switches forward traffic only to the intended recipient, increasing efficiency.
14
In packet switching, what are the advantages of using different routes?
Răspuns
B
C
15
Why are packets sometimes reordered when using packet switching?
Răspuns
(A)
Because each packet may take a different route.
16
What is the function of 'ARP' (Address Resolution Protocol)?
Răspuns
(B)
To resolve IP addresses to MAC addresses.
17
What is the main security risk associated with using symmetric encryption?
Răspuns
(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)?
Răspuns
A
B
19
Which of the following is NOT a characteristic of full-duplex data transmission?
Răspuns
(C)
A single channel is used for transmission.
20
Which of the following statements is true regarding symmetric encryption?
Răspuns
(C)
It uses the same key for encryption and decryption.
21
Which of the following factors influence how data is transmitted?
Răspuns
A
B
C
22
In a network, what task does a router primarily perform?
Răspuns
(B)
Forwarding data packets.
23
Which of the following best describes the operation of an echo check?
Răspuns
(B)
The receiver sends a copy of the data back to the sender to verify it.
24
What is 'social engineering'?
Răspuns
(C)
The practice of manipulating people into revealing confidential information.
25
What kind of error could be detected by parity blocks?
Răspuns
(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?
Răspuns
(C)
Providing network services to applications.
27
Which of the following best describes "automatic repeat request (ARQ)"?
Răspuns
(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?
Răspuns
(B)
A method of error detection.
29
What does the acronym ARQ stand for?
Răspuns
(B)
Automatic Repeat Request
30
What are the common methods for detecting errors in data transmission?
Răspuns
A
B
C
31
What is a 'MAC address' used for?
Răspuns
(A)
To identify a device on a network at the data link layer.
32
What does USB stand for?
Răspuns
(A)
Universal Serial Bus
33
What is the key difference between serial and parallel data transmission?
Răspuns
(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?
Răspuns
(C)
To create a digital signature.
35
Which of the following are examples of network protocols?
Răspuns
A
B
C
D
36
What does 'VPN' stand for?
Răspuns
(A)
Virtual Private Network
37
What is 'spoofing' in a network context?
Răspuns
(B)
An attack where an attacker impersonates a legitimate entity.
38
What is the purpose of a public key in asymmetric encryption?
Răspuns
(B)
To encrypt messages only.
39
What is the primary function of the "header" in a data packet?
Răspuns
(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?
Răspuns
(C)
Full-duplex
41
In the example of ISBN-13 algorithm where 978030640615X, what is the calculation algorithm is used?
Răspuns
(A)
Weighted sum and then divide by 10 to find remainder
42
Why are check digits used?
Răspuns
(C)
To detect errors, such as when data is entered incorrectly.
43
What is the primary benefit of breaking data into packets before transmission?
Răspuns
(C)
It allows data to be sent via a different route.
44
Which of the following protocols is often used to encrypt web traffic?
Răspuns
(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?
Răspuns
(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?
Răspuns
(A)
Symmetric key encryption
47
Which of the following is an example of a "checksum"?
Răspuns
(B)
A hash value used to verify data integrity
48
What is the function of a 'checksum' in data transmission?
Răspuns
(B)
To detect errors in the data.
49
In asymmetric encryption, what happens if someone has your public key?
Răspuns
(B)
They can encrypt messages to you.
50
Which method is most suitable for long-distance communication?
