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Computer Science for IGCSE & O level - Data Transmission (Section 4)

1
Which error detection method is best suited for data transfer over noisy channels?
Answer
(B)
Checksum
2
What is the function of a 'repeater' in a network?
Answer
(B)
To amplify and regenerate signals to extend network range.
3
Which of the following best describes the concept of 'firewall'?
Answer
(B)
A device that filters network traffic.
4
What best describes the role of a 'hub' in a network?
Answer
(B)
Connects devices and broadcasts data to all connected devices.
5
In the ARQ process, how are errors detected?
Answer
(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?
Answer
(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?
Answer
(D)
All of the above.
8
In a network, what does the term 'node' typically refer to?
Answer
(B)
A device that forwards data packets.
9
What does the acronym 'DNS' stand for?
Answer
(B)
Domain Name System
10
What is the primary role of the receiver in an ARQ system?
Answer
(C)
To acknowledge received data or request retransmission.
11
In the context of a USB connection, what happens when a new device is detected?
Answer
(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?
Answer
(A)
0
13
What does the 'Presentation Layer' do in the OSI Model?
Answer
(C)
Formats and encrypts data.
14
What is the difference between even parity and odd parity?
Answer
(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?
Answer
(B)
To manage connections between applications.
16
In the context of error detection, what is a checksum used for?
Answer
(B)
To detect errors in the data transmission.
17
What is the difference between simplex and duplex transmission?
Answer
(A)
Simplex sends data in one direction, duplex in both directions.
18
What advantage does packet switching provide for networks?
Answer
(B)
More efficient use of network resources.
19
Which of the following statement(s) is/are true regarding Quantum cryptography?
Answer
A
D
20
Which of the following is an advantage of packet switching?
Answer
(C)
Can easily re-route data if a line fails.
21
What is the purpose of 'port numbers' in networking?
Answer
(B)
To uniquely identify an application or service running on a device.
22
What is the purpose of a 'protocol' in networking?
Answer
(B)
To establish rules for communication between devices.
23
What is the purpose of error detection in data transmission?
Answer
(C)
To identify transmission errors.
24
What is the key advantage of asymmetric encryption over symmetric encryption?
Answer
(D)
Key exchange is more secure
25
If the 'hop number' of a packet reaches zero, what action is usually taken?
Answer
(C)
The packet is discarded.
26
What is the difference between 'static' and 'dynamic' IP addresses?
Answer
(B)
Static IP addresses are permanent; dynamic IP addresses can change.
27
Which of the following is true about the polarization of the photon?
Answer
B
D
28
Which error detection method involves adding all the 1s in the payload and storing it as a value in the trailer?
Answer
(B)
Checksums.
29
Which of the following factors affect data transmission protocol?
Answer
A
B
C
30
What is the main purpose of parity checking in data transmission?
Answer
(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?
Answer
(C)
Encryption
32
In data transmission, what does the term 'Simplex' refer to?
Answer
(C)
Sending data in only one direction.
33
When using ARQ, if an error is detected, what typically happens?
Answer
(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?
Answer
(B)
Decryption
35
Which of the following is a key benefit of packet switching?
Answer
(B)
More efficient use of network bandwidth.
36
What does a 'tag number' (hop number) do to the header of a packet?
Answer
(A)
It reduces it by one
37
Which technology is specifically based on the use of quantum physics principles?
Answer
(B)
Quantum cryptography.
38
Which data is usually included in an error detection method?
Answer
A
B
C
39
Which error-detection method is best suited for identifying burst errors (multiple bits corrupted)?
Answer
(B)
Checksum
40
What is the main goal of encryption?
Answer
(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?
Answer
(A)
Automatic repeat request
42
What is a 'subnet mask' used for?
Answer
(B)
To identify the network portion of an IP address.
43
Which of the following are essential parts of a data packet?
Answer
A
B
C
44
What is the role of a "check digit"?
Answer
(B)
To detect errors in data entry.
45
What is the main advantage of using checksums for error detection over a simple parity check?
Answer
(A)
Checksums can detect multiple-bit errors more effectively.
46
In the context of data transmission, what does "duplex" refer to?
Answer
(C)
The ability to send and receive data simultaneously.
47
What does the term 'URL' stand for?
Answer
(B)
Uniform Resource Locator
48
Which part of a data transmission system is most vulnerable to errors?
Answer
(C)
The transmission medium.
49
What is the purpose of the 'physical layer' in the OSI model?
Answer
(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?
Answer
(B)
Brute-force attack