Computer Science for IGCSE & O level - Data Transmission (Section 6)
1
Which of these methods require a round-trip of data?
Răspuns
B
D
2
What kind of information are used to generate a check digit?
Răspuns
B
C
D
3
What is the purpose of a 'proxy server'?
Răspuns
(B)
To filter and cache network traffic.
4
Which of the following are examples of network security threats?
Răspuns
A
B
C
5
In the context of asymmetric encryption, who is the sender?
Răspuns
(A)
The follower
6
What is the function of 'segmentation' in data transmission?
Răspuns
(B)
To divide data into smaller, manageable units for transmission.
7
Which is used to identify the errors in data entry?
Răspuns
(B)
Check digits
8
How do echo checks identify errors?
Răspuns
(A)
By sending the data back to the sender.
9
Which of the following are examples of wired network technologies?
Răspuns
A
C
10
What is 'social engineering'?
Răspuns
(B)
The practice of manipulating people to gain information.
11
What distinguishes a full-duplex communication mode?
Răspuns
(B)
Data is sent in both directions simultaneously.
12
Which of the following is NOT a component of a typical packet header?
Răspuns
(C)
The payload.
13
What is the role of a private key in asymmetric encryption?
Răspuns
(C)
Decrypt data that was encrypted with the corresponding public key.
14
What are the common causes of data corruption during transmission?
Răspuns
A
B
C
15
Which of the following is the biggest disadvantage of using asymmetric encryption?
Răspuns
(A)
It is very complex and time-consuming
16
Which of the following is considered a 'layer 1' protocol in the OSI model?
Răspuns
(D)
The physical layer
17
What does the term 'firewall' primarily do in terms of network security?
Răspuns
(B)
Filters network traffic based on predefined rules.
18
What does full-duplex communication allow?
Răspuns
(B)
Data to be sent in both directions simultaneously.
19
What is the purpose of error-checking methods such as checksums and parity bits?
Răspuns
A
C
20
How does 'red-time streaming' relate to packet switching?
Răspuns
(A)
It increases the likelihood of packets getting reordered.
21
What are the key characteristics of serial data transmission?
Răspuns
(A)
Sends bits one at a time over a single channel.
22
What is the role of a sequence number in the packet header?
Răspuns
(B)
To reassemble packets in the correct order.
23
What type of data transmission is commonly used for longer distances?
Răspuns
(C)
Serial
24
Which type of data transmission is usually preferred for long distances?
Răspuns
(B)
Serial data transmission.
25
In the context of ISBN-13 calculation, which operation is used to calculate the check digit?
Răspuns
(B)
Modulo
26
What is the main advantage of asymmetric encryption over symmetric encryption?
Răspuns
(C)
Higher data security
27
What is an example of "plaintext"?
Răspuns
(D)
An email's body before encryption
28
What is the main limitation of using parity checks for error detection?
Răspuns
(A)
It can only detect single-bit errors.
29
What is a key advantage of using packet switching in a network?
Răspuns
(B)
More efficient use of network resources.
30
Which of the following are types of error detection techniques?
Răspuns
A
B
31
What are the benefits of using a USB system?
Răspuns
A
B
C
32
What is the function of the 'sequence number' in a packet's header?
Răspuns
(C)
To help reassemble packets in the correct order.
33
What is the role of the 'payload' in a data packet?
Răspuns
(B)
To contain the actual data being transmitted.
34
How does half-duplex data transmission work?
Răspuns
(B)
Data is sent in one direction at a time.
35
Which of the following uses an excluded value which is a result after blocks of data, the receiving computer also calculates the value from the blocks of data and compares the values?
Răspuns
(C)
Checksum
36
Which layer of the OSI model is responsible for formatting the data before transmission?
Răspuns
(A)
The Presentation Layer
37
What can cause data corruption during transmission?
Răspuns
A
C
38
Which type of transmission mode allows for sending data in only one direction?
Răspuns
(C)
Simplex
39
In the context of data security, what does "encryption" achieve?
Răspuns
(B)
Protects data by converting it into an unreadable format.
40
What is the primary purpose of the OSI model?
Răspuns
(B)
To provide a framework for understanding how networks operate.
41
Which of the following scenarios would be most likely to cause an error detectable by a parity check?
Răspuns
(A)
A single bit is flipped during transmission.
42
What is 'malware'?
Răspuns
(B)
Software designed to damage or disrupt a computer system.
43
What is the primary goal of using error detection methods in data transmission?
Răspuns
(C)
To identify and handle transmission errors.
44
What is a primary advantage of asymmetric encryption?
Răspuns
(B)
Simplified key exchange.
45
Which mode enables two-way communication at the same time?
Răspuns
(C)
Full-duplex
46
Which of the following is true about the security of symmetric encryption?
Răspuns
(A)
The key must be kept secret.
47
What type of error detection involves sending data twice and comparing the two instances?
Răspuns
(C)
Repetition
48
What are the possible causes of data corruption during data transmission?
Răspuns
A
B
C
49
What is the result of the ISBN-13 calculation for the number 978030640615X (where X represents the check digit)?
Răspuns
(C)
2
50
What is the role of 'authentication' in data security?
