For a star topology, which of the following statement(s) is/are not true? I.…

A star topology's fixed-path structure

In a star topology, every node connects to a single central connecting device — commonly a switch, though the same central role can also be played by a hub or a central computer. What defines the topology is the arrangement of paths: every route between two nodes passes through that one central point, and each node attaches to the center with its own link rather than by sharing or extending another node's path. Two structural consequences follow directly: every inter-node path depends on that one central device, so its failure isolates the whole network at once; and the path length (hop count) between any two already-connected nodes stays fixed — node, then center, then node — regardless of how many further nodes later attach, because a newly attached node simply adds its own additional link to the center rather than altering an existing path.

Applying this to Statement I: central-device failure shutting down the entire network follows directly from the first consequence, since every node's path depends on that one device. Statement I is therefore an accurate description of a star topology.

Applying this to Statement II: connecting additional computers increasing the communication time between already-connected nodes contradicts the second consequence — the path length between any two already-connected nodes does not lengthen merely because further nodes attach later, since each new node gets its own separate link to the center. (This is the topology-classification reading of "communication time" — the number of hops on a fixed path — and is distinct from real-world traffic delay, which can rise with load or a central device's own capacity limits regardless of topology; the statement is evaluated here at the topology level, which is what this classification question tests.) Statement II therefore does not accurately describe the star topology's structural property being tested here.

Cross-check against a shared-medium topology such as bus or ring, where the shared path/medium itself is affected as more nodes are attached — there, "more nodes increase communication time" would be a structurally accurate statement about the topology. Star topology avoids this specifically because each node's path to the center is its own dedicated link, independent of every other node's path, which is why the two statements split the way they do here:

• This choice would require Statement I to be the inaccurate one and Statement II to be the accurate one — the opposite of what the fixed-path property implies.

• This choice would require the central-device failure claim itself to be inaccurate, which contradicts the single point of failure a central device creates.

• This choice would require the additional-computers claim to be accurate, which contradicts the fixed path length that keeps existing routes unaffected by later attachments.

Since Statement I holds and Statement II does not, the statement that is not true is exactly Statement II — so "Only II" is the correct choice.