Computer Science for IGCSE & O level - Data Transmission (Section 2)

1
What type of transmission is the parity bit used for?
回答
(C)
Error detection
2
What function does the hop number serve in packet switching?
回答
(B)
To limit the lifespan of a packet.
3
In the context of data transmission, which of the following is a characteristic of the 'Simplex' mode?
回答
(C)
Data can only be sent in one direction.
4
What is the function of the 'sequence number' in a packet's header?
回答
(B)
To ensure the packets are reassembled in the right order.
5
What is the purpose of a 'DNS server'?
回答
(B)
To resolve domain names to IP addresses.
6
What is 'phishing'?
回答
(B)
An attempt to acquire sensitive information by masquerading as a trustworthy entity.
7
Which of the following are methods of detecting errors in data transmission?
回答
A
B
8
When a new device is connected via USB, what typically happens regarding device drivers?
回答
(B)
The device is automatically detected and the operating system attempts to install the appropriate driver.
9
Which of the following is an example of a type of error?
回答
A
B
C
10
What kind of data is transmitted using Serial Data Transmission?
回答
(A)
bits
11
Which of the following is the primary function of the "mod" operation used in ISBN calculations?
回答
(B)
To limit the result to a specific range of values.
12
What is the purpose of the "hop number" in packet switching?
回答
(C)
To prevent packets from circulating endlessly in a network.
13
Which of the following statements best describes a "burst error"?
回答
(C)
An error that affects a contiguous sequence of bits.
14
Which of the following are examples of application layer protocols?
回答
A
C
15
What is the general formula used for the calculation of the check digit in an ISBN-13 number?
回答
(B)
Weighted sum (alternating 1 and 3), modulo 10.
16
Which of the following methods can detect data transmission errors?
回答
A
B
C
17
In the ISBN-13 calculation, the check digit is found by which mathematical operation?
回答
(D)
Modulo
18
What is the main function of 'Cyclic Redundancy Checks' (CRC)?
回答
(C)
To detect transmission errors in the payload.
19
What is a 'domain name'?
回答
(B)
The human-readable address for a website (e.g., example.com).
20
What does the term 'packet switching' refer to?
回答
(C)
The process of breaking data into smaller units before transmission.
21
What is the role of the sender and the receiver in a checksum process?
回答
(A)
The sender calculates the checksum, and the receiver checks it.
22
What is the purpose of the 'sequence number' in a data packet?
回答
(B)
To reassemble packets in the correct order.
23
What is the function of 'Cyclic Redundancy Checks' (CRCs) in data transmission?
回答
(C)
To detect errors in data transmission.
24
What is the primary function of the 'trailer' in a data packet?
回答
(C)
To help with error detection.
25
What are the most common types of errors that can occur during data entry (as mentioned in the context of check digits)?
回答
(A)
Transposition, incorrect digit, and missing a digit.
26
Which error detection technique is the most straightforward?
回答
(B)
Parity check
27
Which factors are commonly considered when determining how data is transmitted?
回答
A
B
C
28
Which type of encryption does not use public and private keys?
回答
(A)
Symmetric encryption
29
In a data transmission, what does the term "serial data transmission" mean?
回答
(A)
Data is sent one bit at a time over a single wire.
30
What is the purpose of 'checksums' in data transmission?
回答
(C)
To detect potential errors.
31
What does the term "ciphertext" refer to?
回答
(C)
The encrypted message.
32
What does the term 'URL' stand for?
回答
(B)
Uniform Resource Locator
33
Which of the following statement(s) is/are true concerning USB?
回答
A
C
34
Which protocol is commonly used for sending emails?
回答
(C)
SMTP
35
Which layer of the OSI model is responsible for providing reliable, connection-oriented communication?
回答
(C)
The Transport Layer
36
What is a "transposition error" in the context of data entry?
回答
(B)
The swapping of two adjacent digits or characters.
37
What is the purpose of error detection methods in data transmission?
回答
(C)
To identify and correct errors introduced during transmission
38
What is the role of the 'session layer' in the OSI model?
回答
(A)
Managing connections between applications.
39
If a byte uses odd parity, and the byte received is 10110010, what should the parity bit be?
回答
(B)
1
40
Which of the following methods is most effective in detecting an error during data entry where the order of two digits is swapped?
回答
(B)
A checksum calculation.
41
If the byte value is 11001010 and odd parity is being used, what is the value of the parity bit?
回答
(A)
0
42
If the byte value is 11001010 and even parity is being used, what is the value of the parity bit?
回答
(B)
1
43
Which of the following is a characteristic of 'symmetric key' encryption?
回答
(C)
The same key is used for both encryption and decryption.
44
What is the function of the 'trailer' in a data packet?
回答
(C)
To indicate the end of the packet.
45
Which type of encryption is used to encrypt a password?
回答
(B)
Symmetric
46
What type of address is used to identify devices on a local network?
回答
(B)
MAC address
47
Which of the following technologies primarily uses radio waves to transmit data?
回答
(C)
Wi-Fi
48
Which component is often used to connect a local network to the internet?
回答
(C)
A router
49
What are checksums used for in data transmission?
回答
(B)
To detect errors in the data.
50
What is a common reason for using packet switching over a dedicated circuit?
回答
(C)
To increase the number of devices that can communicate at once.