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Computer Science for IGCSE & O level - Data Transmission (Section 7)

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