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Computer Science for IGCSE & O level - Data Transmission (Section 10)

1
In parity checking, what is the meaning of 'EVEN' parity?
Answer
(A)
The number of 1s in the byte, including the parity bit, is even.
2
What is the main function of a 'checksum' in data transmission?
Answer
(B)
To verify the integrity of the data.
3
Which type of data transmission is best suited for transmitting data over long distances?
Answer
(B)
Serial data transmission
4
What is the principal function of a 'router' within a computer network?
Answer
(B)
To connect different networks and forward data packets between them.
5
What is the fundamental principle behind an echo check?
Answer
(B)
Error detection.
6
What is the primary purpose of sequence numbers in packetized data transmission?
Answer
(B)
To ensure that data packets are reassembled in the correct order.
7
Which of the following is a characteristic of a 'router'?
Answer
(B)
It connects different networks.
8
Which type of transmission mode does a typical telephone conversation use?
Answer
(C)
Full-duplex
9
What is the goal of error detection techniques?
Answer
(B)
To identify if data was altered or corrupted.
10
What does the term 'backward compatible' mean in the context of USB?
Answer
(B)
Older USB devices work with newer USB ports.
11
What is the primary function of the payload in a packet?
Answer
(B)
To contain the actual data being transmitted.
12
Which technique is typically used to verify data integrity during transmission?
Answer
(C)
Checksums
13
Which type of data transmission allows data to be sent in both directions, but only one direction at a time?
Answer
(B)
Half-duplex
14
Which of the following are common components found in a data packet?
Answer
A
B
C
15
What is the result of encrypting data with a key?
Answer
(B)
Ciphertext
16
If a byte has an odd number of 1s and odd parity is used, what should be the value of the parity bit?
Answer
(B)
0
17
What is the function of the receiving computer when using a checksum?
Answer
(B)
To calculate the checksum value from the data.
18
What is a benefit of using checksums over parity checks for error detection?
Answer
(B)
Checksums can detect multiple-bit errors more effectively.
19
Which data transmission method is used to ensure that the data reaches the recipient?
Answer
(C)
ARQ
20
Which method is used to ensure the data has arrived correctly?
Answer
(D)
Automatic Repeat Request
21
In packet switching, what does the term 'hop number' signify?
Answer
(B)
The number of routers a packet has passed through.
22
What does 'ARQ' primarily aim to achieve?
Answer
(B)
Reliable data transmission.
23
Which of the following statements best describes the function of a router?
Answer
(B)
Forwards data packets between different networks.
24
What can cause data corruption during transmission?
Answer
A
B
C
25
What purpose does the IP address serve in a data packet's header?
Answer
(B)
To identify the source and destination devices.
26
What does the header of a packet typically include?
Answer
A
C
D
27
What is a potential disadvantage of using parity checks?
Answer
(B)
They can only detect errors in a single bit.
28
Which type of data transmission is used in a broadband internet connection?
Answer
(C)
Full-duplex
29
What is the primary function of a 'router' in a computer network?
Answer
(B)
To connect different networks and direct traffic between them.
30
What best describes the role of a hashing algorithm?
Answer
(B)
To create a unique 'fingerprint' of data.
31
In odd parity, how is the parity bit determined?
Answer
(C)
The parity bit is set to ensure the total number of 1s, including the parity bit, is odd.
32
Which of the following is a benefit of USB?
Answer
A
B
C
33
What does the term 'plaintext' refer to in cryptography?
Answer
(C)
The original, unencrypted message.
34
In asymmetric encryption, which key encrypts the data?
Answer
(C)
The receiver's public key.
35
In parity checking, what is the purpose of the parity bit?
Answer
(C)
To detect errors in the data.
36
What type of error is a checksum designed to detect?
Answer
(B)
Errors during transmission
37
What type of data transmission is most suitable for a video conference?
Answer
(C)
Full-duplex
38
What is the function of the 'hop number' in a packet switching network?
Answer
(B)
To prevent packets from circulating indefinitely.
39
What is a key difference between symmetric and asymmetric encryption?
Answer
(A)
Symmetric uses one key; asymmetric uses two.
40
Which key is needed to decrypt a message that was encrypted with a public key?
Answer
(C)
The private key
41
In half-duplex data transmission, data can be sent...
Answer
(C)
In both directions but not at the same time.
42
Which of the following are applications of automatic repeat request(ARQ)? (Select all that apply)
Answer
A
C
D
43
Which encryption method uses the same key to encrypt and decrypt data?
Answer
(B)
Symmetric encryption
44
What is the function of a digital signature?
Answer
(B)
To authenticate the sender and ensure the data's integrity.
45
What problem do check digits help to solve?
Answer
(C)
Errors from typing or scanning.
46
In symmetric encryption, the security of what component is most crucial?
Answer
(C)
The secret key.
47
What is the role of a 'key' in the process of encryption?
Answer
(B)
To transform the plaintext into ciphertext.
48
What does 'redundancy' in CRC refer to?
Answer
(A)
Extra bits added for error detection.
49
Which communication method do you find in a two-way radio?
Answer
(B)
Half-duplex
50
What is the function of the 'sequence number' in a packet header?
Answer
(B)
To ensure all packets reach the destination in the correct order.