Computer Science for IGCSE & O level - Data Transmission (Section 15)
1
What is one of the methods used to generate a check digit?
2
In asymmetric encryption, which key is used for decryption?
3
What method is used to check the integrity of data?
4
Which device is primarily responsible for determining the most efficient path for data packets to reach their destination?
5
In data communication, what does ARQ stand for?
6
Which of the following is NOT a characteristic of ARQ?
Отвечать(C)
Always improving the speed.
7
Which component in a network is responsible for selecting the best route for data packets to their destination?
8
What type of error detection does a checksum fall under?
Отвечать(C)
Block-level error detection
9
In the context of encryption, what is 'plaintext'?
Отвечать(A)
The original, unencrypted data.
10
Why is serial data transmission often preferred for transmitting data over long distances?
Отвечать(B)
Because it uses fewer wires, making cabling simpler and more cost-effective.
11
In the ISBN-13 example, what calculation is made with the digits of the ISBN to calculate the check digit?
Отвечать(B)
Multiply alternate digits by 3 and add them up with the others.
12
What is the resulting output of encrypting a set of data?
13
In cryptography, what is 'plaintext'?
Отвечать(C)
The original, unencrypted message.
14
Which of the following is a characteristic of an echo check?
Отвечать(B)
The sending device receives a copy of the transmitted data to confirm the reception.
15
In the ISBN-13 example, what is the next step after calculating the remainder?
Отвечать(B)
Subtract the remainder from 10
16
Which of the following best describes what 'ciphertext' represents?
Отвечать(C)
The encrypted form of a message.
17
What type of encryption uses a public key and a private key?
Отвечать(B)
Asymmetric-key cryptography
18
What is the role of the check digit?
19
Which of the following is a characteristic of symmetric encryption?
Отвечать(C)
Uses a single key for both encryption and decryption.
20
What does the packet header usually contain?
Отвечать(B)
The IP address of the sending device and IP address of the receiving device
21
What is the purpose of check digits in applications like ISBNs or vehicle identification numbers?
Отвечать(C)
To detect errors introduced by typing or scanning.
22
What differentiates symmetric and asymmetric encryption?
Отвечать(A)
Symmetric encryption uses one key for both encryption and decryption; asymmetric encryption uses two keys.
23
Which of the following techniques is most effective at detecting errors in large data transfers?
24
Which element in a network is responsible for determining the best path for data packets to reach their destination?
25
What type of encryption uses a public key and a private key?
Отвечать(B)
Asymmetric key encryption
26
What is the purpose of a USB-C connector?
Отвечать(C)
To provide high-speed data transfer and power delivery
27
What mechanism does ARQ (Automatic Repeat Request) utilize for reliable data transfer?
Отвечать(B)
Error detection and retransmission.
28
What are common factors that can lead to data corruption during transmission?
29
What is the result of encrypting plaintext?
30
What can a positive acknowledgement signify within an ARQ protocol?
31
In ARQ, what does a positive acknowledgement (ACK) signify?
Отвечать(B)
The data was received without errors.
32
In which type of data transmission can data travel in both directions, but only one way at any given moment?
33
Within a data packet, what is the primary role of the 'payload'?
Отвечать(B)
To carry the actual data being transmitted.
