Computer Science for IGCSE & O level - Data Transmission (Section 7)
1
What is the primary function of the IP address in a data packet?
отговор(C)
To provide the destination address for routing.
2
What is the role of the 'IP address' in a data packet?
отговор(B)
To route the packet to its destination.
3
What is the role of the 'application layer' in the OSI model?
отговор(B)
Providing the interface for applications to access network services.
4
What are the two wires for in a USB cable?
5
What is the role of the 'payload' section of a data packet?
отговор(B)
To contain the actual data being transmitted.
6
Which of the following is a technique used for wireless data transmission?
7
What is the purpose of an ISBN-13 check digit?
отговор(C)
To prevent errors in data entry.
8
In the context of USB, which type of transmission mode is supported?
9
Which of the following is a crucial element for authenticating users?
10
In symmetric encryption, where should the key be stored?
отговор(C)
Privately, with the receiver and the sender.
11
What is the purpose of a 'key' in the encryption process?
отговор(B)
To convert plaintext to ciphertext and vice versa.
12
Which mode of data transmission allows for communication in only one direction?
13
In asymmetric encryption, what is the role of the public key?
14
Which data transmission method permits two-way communication, but only one direction can transmit at a time?
15
Which transmission method is used during a telephone call?
16
In ARQ, what does a negative acknowledgement (NAK) indicate?
отговор(B)
An error in data transmission.
17
In the context of packet switching, what does the 'hop number' indicate?
отговор(B)
The number of routers a packet has passed through.
18
What is the primary role of sequence numbers in data packets?
отговор(B)
To ensure packets are reassembled correctly at the destination.
19
Which type of parity involves setting the parity bit so that the total number of 1s in the data, including the parity bit, is odd?
20
In the context of data transmission, what does 'CRC' stand for?
21
In public-key cryptography, what is the role of the private key?
22
What is the purpose of encryption?
отговор(B)
To protect the confidentiality of data.
23
What is a characteristic of a digital signature?
отговор(B)
It ensures the integrity of the message.
24
Which security principle is ensured by a digital signature?
25
What type of errors do check digits mainly help to prevent?
отговор(B)
Errors during data entry or scanning.
26
What are potential error types that checksums can detect?
27
What method does ARQ use to achieve reliable data transmission?
28
What is the role of the receiver in ARQ?
отговор(B)
To send acknowledgements.
29
What is the main advantage of serial data transmission?
30
What does the receiving computer calculate to check for data transmission errors?
отговор(B)
The number of T-bits in the payload
31
What does a router use to determine the best path for a packet?
отговор(C)
The destination IP address in the header.
32
In the context of data transmission, what is a disadvantage of the parity check?
отговор(A)
It can't detect all errors.
33
What are digital signatures used for?
34
Which of the following are components of a USB cable?
35
When using USB, what usually happens when a device is plugged into a computer?
отговор(B)
The computer automatically detects the device and may install drivers.
36
Which is used to encrypt data?
37
What is the main benefit of packet switching over circuit switching?
38
Which of the following is a characteristic of a strong hashing algorithm?
отговор(B)
It produces a unique hash value for different inputs.
39
What is the role of the 'header' in a data packet?
отговор(B)
To provide information about the packet, such as source and destination addresses.
40
What is the purpose of a digital signature?
отговор(B)
To provide non-repudiation.
41
What type of key is generally kept secret in asymmetric encryption?
42
What is the advantage of check digits in preventing errors?
отговор(B)
They detect errors in typing or scanning.
43
What happens if an error is detected during an echo check?
44
What does the sender typically do with their private key?
45
In which mode of transmission can data flow in both directions at the same time?
46
Which of the following scenarios can check digits help to identify?
47
Which of the following best describes the term 'non-repudiation' in the context of security?
отговор(B)
Preventing a sender from denying they sent a message.
48
Which of the following is NOT a method for error detection?
49
What is the main disadvantage of using parity checks for error detection?
отговор(A)
It can only detect single-bit errors.
50
Within a data packet, what is the role of the 'payload'?
отговор(B)
To hold the actual data being transmitted.
