Computer Science for IGCSE & O level - Data Transmission (Section 8)
1
What is the function of a checksum in data transmission?
Відповідь(B)
To detect errors in the data.
2
When using asymmetric encryption, who typically has the public key?
Відповідь(D)
Anyone who wants to send a message to the receiver.
3
Відповідь(B)
The original, unencrypted data.
4
Which of the following is true regarding the security of the public key in asymmetric encryption?
Відповідь(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?
Відповідь(B)
Reduced complexity in cabling, and therefore lower cost.
9
What is a 'hop number' in packet switching used for?
Відповідь(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?
Відповідь(B)
Lower cost due to simpler wiring.
12
What is the function of the 'header' in a data packet?
Відповідь(B)
To provide information about the packet (e.g., source and destination).
13
What distinguishes symmetric encryption from asymmetric encryption?
Відповідь(A)
Symmetric uses one key; asymmetric uses two.
14
What is the primary purpose of parity checks in the context of data communication?
Відповідь(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?
Відповідь(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?
Відповідь(A)
Serial is better for longer distances
19
Which of the following is a key characteristic of full-duplex data transmission?
Відповідь(C)
Data can be sent in both directions simultaneously.
20
What is the main difference between symmetric and asymmetric key cryptography?
Відповідь(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?
Відповідь(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?
Відповідь(B)
To verify the integrity of the data.
25
When data is encrypted, which of the following happens to the data?
Відповідь(B)
It is transformed into an unreadable format.
26
In the context of encryption, what is meant by 'cipher text'?
Відповідь(C)
The result of encrypting data.
27
What is the result of encrypting the data?
28
What is the main function of a checksum?
Відповідь(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?
Відповідь(B)
To hold the actual data that is being transmitted.
31
What's the purpose of a negative acknowledgment (NAK) within the ARQ protocol?
Відповідь(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?
Відповідь(A)
The number of routers a packet has visited.
35
What is the primary purpose of check digits?
Відповідь(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'?
Відповідь(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?
Відповідь(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?
Відповідь(B)
To detect transmission errors.
45
What security is crucial for symmetric encryption?
Відповідь(C)
Protecting the secret key.
46
Which of the following is a characteristic of symmetric encryption?
Відповідь(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?
Відповідь(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?
