Computer Science for IGCSE & O level - Data Transmission (Section 8)
1
What is the function of a checksum in data transmission?
Trả lời(B)
To detect errors in the data.
2
When using asymmetric encryption, who typically has the public key?
Trả lời(D)
Anyone who wants to send a message to the receiver.
3
Trả lời(B)
The original, unencrypted data.
4
Which of the following is true regarding the security of the public key in asymmetric encryption?
Trả lời(B)
It can be shared with anyone.
5
In the context of quantum cryptography, what does polarization of photons represent?
6
What is typically accomplished by a digital signature?
7
What is the outcome of the encryption process?
8
Which of the following is a key advantage of serial data transmission, especially when compared to parallel transmission?
Trả lời(B)
Reduced complexity in cabling, and therefore lower cost.
9
What is a 'hop number' in packet switching used for?
Trả lời(C)
Preventing packets from circulating indefinitely.
10
What is a key advantage of using packet switching?
11
What is the primary advantage of serial data transmission over parallel data transmission, particularly for long-distance communication?
Trả lời(B)
Lower cost due to simpler wiring.
12
What is the function of the 'header' in a data packet?
Trả lời(B)
To provide information about the packet (e.g., source and destination).
13
What distinguishes symmetric encryption from asymmetric encryption?
Trả lời(A)
Symmetric uses one key; asymmetric uses two.
14
What is the primary purpose of parity checks in the context of data communication?
Trả lời(C)
To detect errors in the transmitted data.
15
In the context of asymmetric encryption, which key is kept confidential?
16
What is the purpose of a check digit in data transmission?
Trả lời(C)
To detect errors in the data
17
What technique is most commonly used for ensuring that data is transmitted without corruption?
18
What is the relationship between serial and parallel data transmission in the context of distance?
Trả lời(A)
Serial is better for longer distances
19
Which of the following is a key characteristic of full-duplex data transmission?
Trả lời(C)
Data can be sent in both directions simultaneously.
20
What is the main difference between symmetric and asymmetric key cryptography?
Trả lời(C)
Symmetric uses a single key, asymmetric uses a key pair.
21
What does the abbreviation 'ARQ' stand for?
22
What is the role of the trailer in a packet?
Trả lời(C)
To detect transmission errors.
23
In asymmetric encryption, what is the private key primarily used for?
24
What is the primary function of a checksum in data transmission?
Trả lời(B)
To verify the integrity of the data.
25
When data is encrypted, which of the following happens to the data?
Trả lời(B)
It is transformed into an unreadable format.
26
In the context of encryption, what is meant by 'cipher text'?
Trả lời(C)
The result of encrypting data.
27
What is the result of encrypting the data?
28
What is the main function of a checksum?
Trả lời(B)
To ensure data integrity.
29
If a byte using even parity contains the bits 1011001, what should the parity bit be?
30
What is the main purpose of the 'payload' section in a data packet?
Trả lời(B)
To hold the actual data that is being transmitted.
31
What's the purpose of a negative acknowledgment (NAK) within the ARQ protocol?
Trả lời(B)
To request a retransmission of the data.
32
Which term describes a message that has been encrypted?
33
What is a common cause of data corruption during transmission?
34
What does the 'hop number' represent in packet switching?
Trả lời(A)
The number of routers a packet has visited.
35
What is the primary purpose of check digits?
Trả lời(B)
To detect data entry errors.
36
In asymmetric encryption, what is the intended use of the public key?
37
Which mode of transmission is employed by a citizen's band (CB) radio?
38
Which of the following can cause data corruption during transmission?
39
In the context of cryptography, what is meant by 'confidentiality'?
Trả lời(B)
Preventing unauthorized disclosure of information.
40
What is a key advantage of serial data transmission regarding the number of wires required?
41
In asymmetric encryption, which key is distributed publicly?
42
What type of acknowledgement indicates that the data has been received successfully?
Trả lời(C)
Positive Acknowledgement (ACK)
43
What term refers to data that has been transformed into an unreadable form?
44
What is the primary function of the parity bit in data transmission?
Trả lời(B)
To detect transmission errors.
45
What security is crucial for symmetric encryption?
Trả lời(C)
Protecting the secret key.
46
Which of the following is a characteristic of symmetric encryption?
Trả lời(C)
Easy to implement and fast.
47
Which of the following error detection methods can detect single-bit errors, and some forms of multi-bit errors?
48
What is the primary function of a Digital Signature?
Trả lời(B)
To verify the integrity and authenticity of the data.
49
What is the term used to describe data that is in an unreadable format?
50
What is an example of block-level error detection?
