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