UGC NET Questions (Paper – 1)

Statements A, B and C correctly distinguish the roles of switches, routers and modems, whereas D is false. Switches are used within LANs, routers direct traffic between networks and modems handle signal conversion. Treating these devices as identical ignores their distinct functions in network design. Therefore, the combination A, B and C only is correct.

Option A:
Option A is incomplete because it recognises switches and routers but omits modems. Since modems are key in many access technologies, the answer should not ignore their role in signal conversion.

Option B:
Option B is correct because it summarises the three main devices and their functions while excluding D, which incorrectly claims they are interchangeable. It reflects typical network architectures used in educational and home settings.

Option C:
Option C is incorrect because it includes only routers and modems and omits switches. Switches are fundamental devices inside LANs, and leaving them out compromises the completeness of the description.

Option D:
Option D is incorrect because it combines A and C with D and thereby accepts D. Claiming that all three devices perform exactly the same function is technically wrong and misleads learners about basic networking concepts.

Routers operate at the network layer and use logical IP addresses in routing tables to determine the best path for packets. They interconnect different networks, such as linking a local area network to the wider internet. This makes them fundamental components in complex network architectures. Therefore, the device described is a router.

Option A:
Option A, switch, primarily operates at the data link layer and forwards frames within a single local network segment rather than between different networks. It does not typically make routing decisions based on network layer addresses.

Option B:
Option B, hub, is a basic device that simply repeats incoming electrical signals to all ports without any intelligent forwarding, and it does not examine logical addresses.

Option C:
Option C is correct because routers are defined by their ability to connect multiple networks and route packets based on IP addressing information. This matches the description given in the question.

Option D:
Option D, repeater, amplifies or regenerates signals to extend the distance they can travel on a cable but does not make decisions about packet paths between networks.