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Computer Science for IGCSE & O level - Data Transmission (Section 12)

1
What are some common causes of data corruption during transmission?
Answer
A
B
2
What is the main purpose of a 'router' within a computer network?
Answer
(B)
To connect different networks and forward data packets.
3
What is the primary function of parity checks?
Answer
(B)
To detect errors in data transmission.
4
What does a checksum do?
Answer
(B)
Compares two values of data to check data integrity.
5
What is the purpose of check digits?
Answer
(B)
To identify typing errors.
6
In asymmetric encryption, which key is used to decrypt a message?
Answer
(D)
The recipient's private key.
7
In a data packet, what is the main function of the 'trailer' section?
Answer
(B)
To help detect transmission errors.
8
What is the main difference between half-duplex and full-duplex data transmission?
Answer
(A)
Half-duplex transmits data in one direction, full-duplex transmits data in two directions simultaneously.
9
In a network, what is a common function of a router?
Answer
(C)
To connect multiple networks together.
10
When using even parity, and the data byte is 11010010, what should the parity bit be?
Answer
(B)
1
11
What is the primary purpose of using a 'check digit' in data transmission?
Answer
(B)
To detect errors that may have occurred.
12
What's a defining feature of symmetric encryption?
Answer
(C)
It employs a single key for both encryption and decryption.
13
In an echo check, what is sent back to the sender?
Answer
(A)
The original data
14
Which of the following is the biggest disadvantage of using asymmetric encryption?
Answer
(A)
It is very complex and time consuming
15
In data transmission, which of these ensures that the correct data is received?
Answer
B
C
16
Which transmission mode allows data transfer in only one direction?
Answer
(A)
Simplex
17
In symmetric encryption, what is used for both encryption and decryption?
Answer
(C)
A single, shared secret key
18
What are the main components of a packet?
Answer
(B)
Header, payload, and trailer
19
Which of the following techniques is used for error detection?
Answer
(C)
Checksums
20
What is the purpose of using a public key in asymmetric encryption?
Answer
(C)
To encrypt the data.
21
Which of the following best describes what 'plaintext' means in data security?
Answer
(A)
The unencrypted data.
22
What is the main goal of encryption?
Answer
(C)
To make data unreadable to unauthorized users.
23
What is the term used for the encrypted data?
Answer
(B)
Ciphertext
24
What do you call the original format of a message before it is processed through an encryption algorithm?
Answer
(C)
Plaintext
25
What is the main function of encryption?
Answer
(B)
To prevent unauthorized access to data.
26
When does data corruption most likely occur?
Answer
(A)
When the connection is poor
27
In the context of data packets, what does 'payload' mean?
Answer
(B)
The data itself that is being transmitted.
28
In packet switching, what information does the 'hop number' represent?
Answer
(B)
The number of routers the packet has traversed.
29
What does the sender typically do with the public key in an asymmetric system?
Answer
(B)
Share it with anyone.
30
Which of the following can lead to data corruption during transmission?
Answer
A
B
31
What is the main goal of using a digital signature?
Answer
(B)
To provide message authenticity and non-repudiation.
32
What type of error can block parity detect?
Answer
(C)
Errors where a single bit is changed in any byte.
33
What is a potential vulnerability when using symmetric encryption?
Answer
(A)
The key exchange process.
34
What is the core purpose of encryption?
Answer
(B)
To make data unreadable to unauthorized parties.
35
Which of the following is a disadvantage of serial data transmission?
Answer
(A)
Slower transmission rates over longer distances.
36
What is the main purpose of check digits in data entry?
Answer
(B)
To detect typing or scanning errors.
37
Which method is used to reverse the encryption process?
Answer
(B)
Decryption
38
Which method of transmission sends data one bit at a time?
Answer
(C)
Serial data transmission
39
What type of error can parity checks detect?
Answer
(A)
Errors in a single bit.
40
In a walkie-talkie, what type of data transmission is employed?
Answer
(B)
Half-duplex
41
What is a checksum used for?
Answer
B
D
42
What is the purpose of a checksum?
Answer
(B)
To ensure data integrity during transmission.
43
If even parity is used, and the data being sent is 1101010, what should the parity bit be set to?
Answer
(A)
0
44
What does the section on check digits mention they are used for?
Answer
(C)
To detect errors from typing or scanning.
45
In the context of data security, what does 'non-repudiation' mean?
Answer
(C)
The sender cannot deny having sent a message.
46
If an error is detected during data transmission using ARQ, what happens next?
Answer
(C)
The data is retransmitted.
47
Which type of encryption uses a single secret key for both encryption and decryption?
Answer
(B)
Symmetric encryption
48
What key must be kept secret in symmetric encryption?
Answer
(C)
Secret key
49
What key is used to encrypt data in asymmetric encryption?
Answer
(A)
A public key.
50
In the context of data transmission, what is 'synchronization' primarily concerned with?
Answer
(C)
Ensuring the sender and receiver are coordinated.