Computer Science for IGCSE & O level - Data Transmission (Section 4)
1
Which error detection method is best suited for data transfer over noisy channels?
2
What is the function of a 'repeater' in a network?
отговор(B)
To amplify and regenerate signals to extend network range.
3
Which of the following best describes the concept of 'firewall'?
отговор(B)
A device that filters network traffic.
4
What best describes the role of a 'hub' in a network?
отговор(B)
Connects devices and broadcasts data to all connected devices.
5
In the ARQ process, how are errors detected?
отговор(D)
By calculating a checksum on the data before transmission.
6
Which of the following best describes how data is transferred using parallel data transmission?
отговор(C)
Data is sent multiple bits at a time over several wires.
7
Which of the following can be applied on both serial and parallel data transmission?
8
In a network, what does the term 'node' typically refer to?
отговор(B)
A device that forwards data packets.
9
What does the acronym 'DNS' stand for?
10
What is the primary role of the receiver in an ARQ system?
отговор(C)
To acknowledge received data or request retransmission.
11
In the context of a USB connection, what happens when a new device is detected?
отговор(C)
The device is automatically recognized and the appropriate device driver software is loaded.
12
If a byte uses even parity, and the byte received is 10110010, what should the parity bit be?
13
What does the 'Presentation Layer' do in the OSI Model?
отговор(C)
Formats and encrypts data.
14
What is the difference between even parity and odd parity?
отговор(A)
Even parity means the number of 1s in the byte is even; odd parity means the number of 1s in the byte is odd.
15
What is the purpose of the 'session layer' in the OSI model?
отговор(B)
To manage connections between applications.
16
In the context of error detection, what is a checksum used for?
отговор(B)
To detect errors in the data transmission.
17
What is the difference between simplex and duplex transmission?
отговор(A)
Simplex sends data in one direction, duplex in both directions.
18
What advantage does packet switching provide for networks?
отговор(B)
More efficient use of network resources.
19
Which of the following statement(s) is/are true regarding Quantum cryptography?
20
Which of the following is an advantage of packet switching?
отговор(C)
Can easily re-route data if a line fails.
21
What is the purpose of 'port numbers' in networking?
отговор(B)
To uniquely identify an application or service running on a device.
22
What is the purpose of a 'protocol' in networking?
отговор(B)
To establish rules for communication between devices.
23
What is the purpose of error detection in data transmission?
отговор(C)
To identify transmission errors.
24
What is the key advantage of asymmetric encryption over symmetric encryption?
отговор(D)
Key exchange is more secure
25
If the 'hop number' of a packet reaches zero, what action is usually taken?
26
What is the difference between 'static' and 'dynamic' IP addresses?
отговор(B)
Static IP addresses are permanent; dynamic IP addresses can change.
27
Which of the following is true about the polarization of the photon?
28
Which error detection method involves adding all the 1s in the payload and storing it as a value in the trailer?
29
Which of the following factors affect data transmission protocol?
30
What is the main purpose of parity checking in data transmission?
отговор(B)
To detect errors that may have occurred during transmission.
31
In data transmission, which of the following is NOT a typical method for error detection?
32
In data transmission, what does the term 'Simplex' refer to?
отговор(C)
Sending data in only one direction.
33
When using ARQ, if an error is detected, what typically happens?
отговор(B)
The receiver sends a NAK to the sender.
34
What is the name of the process of converting the encrypted message back to a readable form?
35
Which of the following is a key benefit of packet switching?
отговор(B)
More efficient use of network bandwidth.
36
What does a 'tag number' (hop number) do to the header of a packet?
37
Which technology is specifically based on the use of quantum physics principles?
38
Which data is usually included in an error detection method?
39
Which error-detection method is best suited for identifying burst errors (multiple bits corrupted)?
40
What is the main goal of encryption?
отговор(B)
To convert the data into an unreadable format.
41
Which of the following is a form of error detection that makes use of a system of acknowledgements and timeouts?
42
What is a 'subnet mask' used for?
отговор(B)
To identify the network portion of an IP address.
43
Which of the following are essential parts of a data packet?
44
What is the role of a "check digit"?
отговор(B)
To detect errors in data entry.
45
What is the main advantage of using checksums for error detection over a simple parity check?
отговор(A)
Checksums can detect multiple-bit errors more effectively.
46
In the context of data transmission, what does "duplex" refer to?
отговор(C)
The ability to send and receive data simultaneously.
47
What does the term 'URL' stand for?
48
Which part of a data transmission system is most vulnerable to errors?
49
What is the purpose of the 'physical layer' in the OSI model?
отговор(C)
To define the physical transmission media.
50
Which security threat involves an attacker attempting to guess a password or key through trial and error?
