1. Data communication refers to:
A) Process of storing data
B) Process of transmitting data between devices
C) Process of securing data
D) Process of analyzing data
Answer: B) Process of transmitting data between devices
Explanation: Data communication involves transferring digital or analog data between devices via transmission media.
2. Which of the following is not a component of data communication?
A) Message
B) Sender
C) Receiver
D) Compiler
Answer: D) Compiler
Explanation: The main components are message, sender, receiver, medium, and protocol.
3. What does “protocol” mean in networking?
A) A set of rules for communication
B) A physical medium
C) A type of message
D) An error in communication
Answer: A) A set of rules for communication
Explanation: Protocols are standard rules that govern data transmission between devices.
4. Which transmission mode allows data to be sent in both directions simultaneously?
A) Simplex
B) Half-duplex
C) Full-duplex
D) Multiplex
Answer: C) Full-duplex
Explanation: Full-duplex allows simultaneous two-way communication.
5. Which device connects two different networks?
A) Switch
B) Hub
C) Router
D) Repeater
Answer: C) Router
Explanation: A router routes data packets between different networks.
6. Which of the following is NOT a guided transmission medium?
A) Coaxial cable
B) Fiber optic cable
C) Twisted pair cable
D) Radio waves
Answer: D) Radio waves
Explanation: Radio waves are unguided (wireless) media.
7. In networking, bandwidth refers to:
A) Size of data
B) Data transmission capacity of a channel
C) Delay in communication
D) Storage capacity
Answer: B) Data transmission capacity of a channel
Explanation: Bandwidth indicates maximum data rate supported by a medium.
8. Which of the following uses light for data transmission?
A) Coaxial cable
B) Fiber optic cable
C) Twisted pair cable
D) Satellite
Answer: B) Fiber optic cable
Explanation: Fiber optics use light pulses to transmit data.
9. Which layer of the OSI model deals with routing of data?
A) Data link layer
B) Network layer
C) Transport layer
D) Physical layer
Answer: B) Network layer
Explanation: Network layer handles logical addressing and routing of packets.
10. Which OSI layer is responsible for error detection and correction?
A) Physical layer
B) Data link layer
C) Transport layer
D) Application layer
Answer: B) Data link layer
Explanation: Data link layer ensures reliable node-to-node communication with error checking.
11. In OSI model, which layer provides encryption and compression?
A) Session layer
B) Transport layer
C) Presentation layer
D) Network layer
Answer: C) Presentation layer
Explanation: The presentation layer translates, compresses, and encrypts data.
12. Which protocol is used to send emails?
A) HTTP
B) SMTP
C) FTP
D) SNMP
Answer: B) SMTP
Explanation: SMTP (Simple Mail Transfer Protocol) is used to send emails.
13. Which protocol is used to retrieve emails?
A) FTP
B) POP3 / IMAP
C) SMTP
D) HTTP
Answer: B) POP3 / IMAP
Explanation: POP3 and IMAP are used to retrieve emails from mail servers.
14. IP address of version 4 (IPv4) is of:
A) 16 bits
B) 32 bits
C) 64 bits
D) 128 bit
Answer: B) 32 bits
Explanation: IPv4 addresses are 32-bit numerical addresses written in dotted decimal form.
15. IPv6 addresses are:
A) 64-bit
B) 128-bit
C) 256-bit
D) 32-bit
Answer: B) 128-bit
Explanation: IPv6 uses 128-bit addresses to provide a large address space.
16. Which protocol is used for transferring files?
A) FTP
B) SMTP
C) SNMP
D) ICMP
Answer: A) FTP
Explanation: FTP (File Transfer Protocol) transfers files over a network.
17. Which network device operates at Data Link Layer?
A) Router
B) Switch
C) Hub
D) Gateway
Answer: B) Switch
Explanation: A switch forwards data based on MAC addresses, operating at the Data Link Layer.
18. Which of the following is NOT an application layer protocol?
A) HTTP
B) FTP
C) DNS
D) TCP
Answer: D) TCP
Explanation: TCP is a Transport layer protocol, not Application layer.
19. Which topology has a single central cable to which all nodes are connected?
A) Star
B) Mesh
C) Bus
D) Ring
Answer: C) Bus
Explanation: In bus topology, a single backbone cable connects all devices.
20. Which topology connects each node directly to every other node?
A) Bus
B) Ring
C) Mesh
D) Star
Answer: C) Mesh
Explanation: Mesh topology provides dedicated links between each pair of nodes.
21. In star topology, all computers are connected to:
A) Each other
B) A central hub or switch
C) Backbone cable
D) Router
Answer: B) A central hub or switch
Explanation: Star topology requires a central device for communication.
22. What is the main disadvantage of ring topology?
A) High cost
B) Failure of one node affects the whole network
C) Difficult to install
D) No central control
Answer: B) Failure of one node affects the whole network
Explanation: In a ring, if one computer or connection fails, it can break the communication path.
23. Which of the following is a wireless communication technology?
A) Bluetooth
B) Wi-Fi
C) Infrared
D) All of the above
Answer: D) All of the above
Explanation: Bluetooth, Wi-Fi, and Infrared are wireless technologies.
24. Which is the fastest wireless communication technology among these?
A) Bluetooth
B) Infrared
C) Wi-Fi
D) Ethernet
Answer: C) Wi-Fi
Explanation: Wi-Fi provides higher data transfer rates than Bluetooth and Infrared.
25. Which organization developed the OSI model?
A) IEEE
B) ISO
C) IETF
D) W3C
Answer: B) ISO
Explanation: International Organization for Standardization (ISO) developed the OSI reference model.
26. Which of the following is a private IP address?
A) 192.168.1.1
B) 8.8.8.8
C) 172.33.10.5
D) 120.10.10.1
Answer: A) 192.168.1.1
Explanation: 192.168.x.x is reserved for private networks.
27. Which protocol is used to translate domain names into IP addresses?
A) HTTP
B) DNS
C) DHCP
D) SNMP
Answer: B) DNS
Explanation: Domain Name System (DNS) resolves domain names into IP addresses.
28. DHCP is used for:
A) Assigning IP addresses automatically
B) Sending emails
C) File transfer
D) Encryption
Answer: A) Assigning IP addresses automatically
Explanation: DHCP (Dynamic Host Configuration Protocol) assigns IP addresses dynamically.
29. Which of the following is NOT a valid class of IPv4 addresses?
A) Class A
B) Class B
C) Class D
D) Class F
Answer: D) Class F
Explanation: IPv4 has classes A, B, C, D (multicast), and E (experimental). No Class F exists.
30. In IPv4, the range of Class C addresses is:
A) 1–126
B) 128–191
C) 192–223
D) 224–239
Answer: C) 192–223
Explanation: Class C IP addresses range from 192.0.0.0 to 223.255.255.255.
31. Which device works at the physical layer?
A) Switch
B) Repeater
C) Router
D) Gateway
Answer: B) Repeater
Explanation: Repeaters regenerate signals at the physical layer.
32. Which protocol is used for secure communication over the web?
A) HTTP
B) HTTPS
C) FTP
D) TELNET
Answer: B) HTTPS
Explanation: HTTPS uses SSL/TLS for encrypted web communication.
33. Which of the following is a connection-oriented protocol?
A) UDP
B) IP
C) TCP
D) ICMP
Answer: C) TCP
Explanation: TCP ensures reliable, connection-oriented communication.
34. Which of the following is a connectionless protocol?
A) TCP
B) UDP
C) FTP
D) HTTP
Answer: B) UDP
Explanation: UDP is connectionless and does not guarantee delivery.
35. In TCP/IP, IP provides:
A) Reliability
B) Routing and addressing
C) Encryption
D) Error recovery
Answer: B) Routing and addressing
Explanation: IP handles logical addressing and routing, not reliability.
36. Which protocol is used to monitor and manage networks?
A) SMTP
B) SNMP
C) FTP
D) POP3
Answer: B) SNMP
Explanation: SNMP (Simple Network Management Protocol) is used for monitoring and management.
37. Which of the following is NOT a wireless standard?
A) 802.11
B) 802.15
C) 802.3
D) Bluetooth
Answer: C) 802.3
Explanation: 802.3 is Ethernet (wired). Wireless standards include 802.11 (Wi-Fi) and 802.15 (Bluetooth).
38. The delay caused by the time it takes a signal to travel from source to destination is called:
A) Transmission delay
B) Propagation delay
C) Processing delay
D) Queuing delay
Answer: B) Propagation delay
Explanation: Propagation delay is due to signal travel time across the medium.
39. The time taken to put all packet bits onto the transmission medium is:
A) Transmission delay
B) Propagation delay
C) Processing delay
D) Queuing delay
Answer: A) Transmission delay
Explanation: Transmission delay depends on packet size and transmission rate.
40. Which of the following uniquely identifies a device on a local network?
A) IP address
B) Port number
C) MAC address
D) Subnet mask
Answer: C) MAC address
Explanation: A MAC address uniquely identifies a device’s network interface card (NIC).
41. Which of the following is an example of circuit switching?
A) Internet browsing
B) Telephone network
C) Email
D) File download
Answer: B) Telephone network
Explanation: Traditional telephone networks use circuit switching.
42. Which of the following is an example of packet switching?
A) PSTN
B) Internet
C) Telegraph
D) Radio broadcasting
Answer: B) Internet
Explanation: Internet communication uses packet switching.
43. The smallest unit of data in a network is called:
A) Segment
B) Frame
C) Packet
D) Bit
Answer: D) Bit
Explanation: A bit (binary digit) is the smallest data unit in networking.
44. In OSI model, segmentation and reassembly occur at which layer?
A) Data link
B) Network
C) Transport
D) Application
Answer: C) Transport
Explanation: Transport layer breaks data into segments and reassembles them at destination.
45. In computer networks, QoS stands for:
A) Quality of Software
B) Quality of Service
C) Query on System
D) Quick Operating System
Answer: B) Quality of Service
Explanation: QoS ensures performance guarantees like bandwidth, delay, and jitter.
46. Which protocol is used to ping a host?
A) ICMP
B) TCP
C) UDP
D) ARP
Answer: A) ICMP
Explanation: ICMP (Internet Control Message Protocol) is used for diagnostic functions like ping.
47. Which protocol is used to resolve IP address to MAC address?
A) RARP
B) ARP
C) ICMP
D) DHCP
Answer: B) ARP
Explanation: Address Resolution Protocol (ARP) maps IP addresses to MAC addresses.
48. Which protocol maps MAC address to IP address?
A) RARP
B) ARP
C) ICMP
D) DNS
Answer: A) RARP
Explanation: Reverse ARP (RARP) maps a device’s MAC address to its IP address.
49. Which of the following is NOT a function of transport layer?
A) Error detection
B) Flow control
C) Routing
D) Segmentation
Answer: C) Routing
Explanation: Routing is handled by the network layer, not the transport layer.
50. In TCP/IP model, which layer corresponds to OSI application, presentation, and session layers combined?
A) Transport layer
B) Network layer
C) Application layer
D) Data link layer
Answer: C) Application layer
Explanation: TCP/IP application layer combines OSI’s top three layers.
51. Which of the following is not a guided transmission medium?
A) Coaxial cable
B) Twisted pair cable
C) Fiber optic cable
D) Radio waves
Answer: D) Radio waves
Explanation: Radio waves are unguided transmission media, whereas coaxial, twisted pair, and fiber optics are guided.
52. The main disadvantage of optical fiber is:
A) High bandwidth
B) Lightweight
C) Fragile and costly
D) Immune to EMI
Answer: C) Fragile and costly
Explanation: Fiber optics offer high speed and immunity to interference but are expensive and delicate.
53. Which transmission medium is least affected by electromagnetic interference?
A) Twisted pair
B) Coaxial cable
C) Optical fiber
D) Microwave
Answer: C) Optical fiber
Explanation: Optical fibers use light instead of electricity, hence immune to EMI.
54. Switching technique where the whole message is sent as a single unit is:
A) Circuit switching
B) Message switching
C) Packet switching
D) Time switching
Answer: B) Message switching
Explanation: In message switching, the entire message is stored and forwarded, unlike packet switching.
55. In circuit switching, a path is established:
A) Only when needed
B) Permanently
C) For each packet separately
D) Without confirmation
Answer: A) Only when needed
Explanation: Circuit switching establishes a dedicated path for the entire session, then releases it.
56. The Internet uses which switching technique?
A) Circuit switching
B) Message switching
C) Packet switching
D) Frequency switching
Answer: C) Packet switching
Explanation: The Internet breaks data into packets which are routed independently.
57. Which of the following is a disadvantage of circuit switching?
A) Guaranteed bandwidth
B) Inefficient resource utilization
C) Suitable for real-time voice
D) Connection-oriented
Answer: B) Inefficient resource utilization
Explanation: Once a circuit is established, resources remain reserved even if not fully used.
58. Packet switching can be classified as:
A) Datagram and virtual circuit
B) Message and datagram
C) Circuit and virtual path
D) Bit and byte
Answer: A) Datagram and virtual circuit
Explanation: Packet switching has two approaches: connectionless (datagram) and connection-oriented (virtual circuit).
59. In message switching, each message is stored at:
A) Sender side only
B) Receiver side only
C) Intermediate nodes
D) Router buffers only
Answer: C) Intermediate nodes
Explanation: Message switching uses the store-and-forward technique at each intermediate node.
60. In OSI model, which layer handles routing and addressing?
A) Physical layer
B) Data link layer
C) Network layer
D) Transport layer
Answer: C) Network layer
Explanation: The network layer is responsible for logical addressing and path determination (routing).
61. TCP/IP model combines OSI’s session, presentation, and application layers into:
A) Session layer
B) Application layer
C) Transport layer
D) Network layer
Answer: B) Application layer
Explanation: The TCP/IP model has fewer layers; the top three OSI layers merge into Application layer.
62. Which protocol provides reliable, connection-oriented service?
A) UDP
B) TCP
C) IP
D) ICMP
Answer: B) TCP
Explanation: TCP ensures reliability using acknowledgments, sequencing, and retransmission.
63. Which protocol is used for quick transmission without reliability?
A) TCP
B) UDP
C) IP
D) FTP
Answer: B) UDP
Explanation: UDP is connectionless and fast, suitable for streaming and gaming where speed matters more.
64. IP is responsible for:
A) Error detection
B) Reliable delivery
C) Logical addressing and routing
D) Encryption
Answer: C) Logical addressing and routing
Explanation: IP provides logical addressing (IP addresses) and routing packets between networks.
65. Which protocol is used for error reporting in IP?
A) ARP
B) ICMP
C) IGMP
D) DHCP
Answer: B) ICMP
Explanation: ICMP (Internet Control Message Protocol) is used for error messages like “destination unreachable.”
66. Which protocol translates IP address to MAC address?
A) RARP
B) ARP
C) DHCP
D) ICMP
Answer: B) ARP
Explanation: ARP (Address Resolution Protocol) maps logical (IP) address to physical (MAC) address.
67. Which version of IP provides 128-bit addresses?
A) IPv4
B) IPv5
C) IPv6
D) ICMPv6
Answer: C) IPv6
Explanation: IPv6 uses 128-bit addressing, providing a huge address space compared to 32-bit IPv4.
68. Which protocol assigns dynamic IP addresses?
A) DNS
B) ARP
C) DHCP
D) ICMP
Answer: C) DHCP
Explanation: DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses to devices.
69. DNS works on which layer of OSI model?
A) Network layer
B) Transport layer
C) Application layer
D) Data link layer
Answer: C) Application layer
Explanation: DNS is an application layer protocol that translates domain names to IP addresses.
70. Which record type in DNS maps a domain name to an IP address?
A) MX record
B) A record
C) CNAME record
D) PTR record
Answer: B) A record
Explanation: An “A” (Address) record maps a hostname to its IPv4 address.
71. Which protocol is used to transfer files over the Internet?
A) SMTP
B) FTP
C) HTTP
D) SNMP
Answer: B) FTP
Explanation: FTP (File Transfer Protocol) is used for file uploading and downloading.
72. Which protocol is used for sending email?
A) FTP
B) SMTP
C) POP3
D) HTTP
Answer: B) SMTP
Explanation: SMTP (Simple Mail Transfer Protocol) is used to send emails from client to server.
73. Which protocol is used for receiving email into a local client?
A) SMTP
B) POP3
C) FTP
D) DHCP
Answer: B) POP3
Explanation: POP3 (Post Office Protocol) allows downloading emails from the server to client.
74. Which protocol is an alternative to POP3 and allows server-side email management?
A) IMAP
B) DHCP
C) SMTP
D) ICMP
Answer: A) IMAP
Explanation: IMAP (Internet Message Access Protocol) lets users read, organize, and manage emails without downloading them.
75. Which protocol is used for browsing web pages?
A) FTP
B) HTTP
C) SMTP
D) DNS
Answer: B) HTTP
Explanation:HTTP is the protocol used by web browsers and web servers to communicate and transfer web pages over the Internet.
76. Which protocol is used for secure communication over the web?
A) HTTP
B) HTTPS
C) FTP
D) SMTP
Answer: B) HTTPS
Explanation: HTTPS (HTTP Secure) uses SSL/TLS to encrypt web traffic for security.
77. Which of the following is a network security device that monitors and controls traffic?
A) Hub
B) Switch
C) Firewall
D) Repeater
Answer: C) Firewall
Explanation: A firewall filters and controls incoming and outgoing network traffic based on rules.
78. Which type of attack floods a system with requests to exhaust resources?
A) Phishing
B) DoS
C) Spoofing
D) Sniffing
Answer: B) DoS
Explanation: Denial of Service (DoS) attack makes a system unavailable by overwhelming it with traffic.
79. A VPN provides security by using:
A) Encryption
B) Compression
C) Frequency hopping
D) Bandwidth allocation
Answer: A) Encryption
Explanation: Virtual Private Network (VPN) encrypts communication between remote users and networks.
80. WPA2 is a security protocol used in:
A) Bluetooth
B) Wi-Fi
C) Ethernet
D) Satellite
Answer: B) Wi-Fi
Explanation: WPA2 (Wi-Fi Protected Access 2) secures wireless networks with strong encryption.
81. Which encryption method uses two different keys (public and private)?
A) Symmetric
B) Asymmetric
C) Hashing
D) Stream cipher
Answer: B) Asymmetric
Explanation: Asymmetric encryption uses a public-private key pair (e.g., RSA).
82. The process of converting plain text into coded text is called:
A) Decryption
B) Encryption
C) Encoding
D) Hashing
Answer: B) Encryption
Explanation: Encryption ensures confidentiality by converting plaintext into ciphertext.
83. Which protocol is used for secure file transfer?
A) FTP
B) SFTP
C) HTTP
D) POP3
Answer: B) SFTP
Explanation: SFTP (Secure FTP) uses SSH for secure file transfer.
84. SSL stands for:
A) Secure Socket Layer
B) System Security Layer
C) Software Socket Layer
D) Secure System Log
Answer: A) Secure Socket Layer
Explanation: SSL is a protocol for securing communication between client and server, replaced by TLS.
85. In wireless communication, which frequency band is commonly used by Wi-Fi?
A) 2.4 GHz and 5 GHz
B) 900 MHz
C) 7 GHz
D) 100 MHz
Answer: A) 2.4 GHz and 5 GHz
Explanation: Wi-Fi networks typically operate in 2.4 GHz and 5 GHz ISM bands.
86. Which wireless standard provides the fastest speed?
A) 802.11a
B) 802.11b
C) 802.11g
D) 802.11ac
Answer: D) 802.11ac
Explanation: 802.11ac supports gigabit speeds and is faster than previous Wi-Fi standards.
87. Bluetooth technology is based on:
A) Infrared
B) Radio waves
C) Microwave
D) Optical fiber
Answer: B) Radio waves
Explanation: Bluetooth operates in the 2.4 GHz radio frequency band.
88. In mobile communication, 4G provides speeds up to:
A) 1 Mbps
B) 10 Mbps
C) 100 Mbps or more
D) 1 Gbps
Answer: C) 100 Mbps or more
Explanation: 4G networks typically provide up to 100 Mbps for mobile and up to 1 Gbps for stationary users.
89. 5G technology primarily focuses on:
A) Voice calls
B) High latency
C) Ultra-low latency and high speed
D) Only text messaging
Answer: C) Ultra-low latency and high speed
Explanation: 5G supports massive IoT, ultra-low latency, and multi-gigabit speeds.
90. Which satellite communication orbit is closest to Earth?
A) GEO
B) MEO
C) LEO
D) HEO
Answer: C) LEO
Explanation: Low Earth Orbit (LEO) satellites are closest, typically 500–2000 km above Earth.
91. Which switching technique is mostly used in telephone networks?
A) Packet switching
B) Circuit switching
C) Message switching
D) Frequency switching
Answer: B) Circuit switching
Explanation: Traditional telephone systems use circuit switching for dedicated communication.
92. Which device is used to regenerate signals in networking?
A) Switch
B) Router
C) Repeater
D) Hub
Answer: C) Repeater
Explanation: Repeaters regenerate and amplify weak signals to extend the transmission distance.
93. Which device works at the data link layer?
A) Router
B) Switch
C) Repeater
D) Modem
Answer: B) Switch
Explanation: Switches operate at Layer 2 of the OSI model and forward frames based on MAC addresses.
94. Which device connects two different networks?
A) Switch
B) Router
C) Hub
D) Repeater
Answer: B) Router
Explanation: A router connects multiple networks and forwards packets based on IP addresses.
95. Which protocol is used for remote login?
A) FTP
B) SSH
C) SMTP
D) HTTP
Answer: B) SSH
Explanation: SSH (Secure Shell) allows secure remote login and command execution.
96. Cloud computing primarily depends on:
A) Local servers
B) Centralized power supply
C) Virtualization and networking
D) Optical disks
Answer: C) Virtualization and networking
Explanation: Cloud computing relies on virtualization for resource sharing and networking for connectivity.
97. Which is not a cloud service model?
A) IaaS
B) PaaS
C) SaaS
D) BIOS
Answer: D) BIOS
Explanation: IaaS, PaaS, and SaaS are cloud models; BIOS is related to computer hardware.
98. IoT (Internet of Things) devices are typically connected using:
A) Satellite only
B) Wired Ethernet only
C) Wireless technologies like Wi-Fi, Zigbee
D) Magnetic waves
Answer: C) Wireless technologies like Wi-Fi, Zigbee
Explanation: IoT devices often use Wi-Fi, Zigbee, LoRa, or Bluetooth for connectivity.
99. In networking, latency refers to:
A) Bandwidth
B) Delay in data transmission
C) Error rate
D) Packet loss
Answer: B) Delay in data transmission
Explanation: Latency is the time taken for data to travel from source to destination.
100. Which organization standardizes Internet protocols?
A) IEEE
B) IETF
C) ISO
D) ITU
Answer: B) IETF
Explanation: The Internet Engineering Task Force (IETF) develops and standardizes Internet protocols.
nation: HTTP (HyperText Transfer Protocol) is the foundation for web communication between browsers and servers.