In network planning for civil engineering projects, identify the incorrect statement about activities, events, nodes, and networks.
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AAn activity is the time-consuming part of a project (it requires resources and has duration).
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BThe beginning and end of a job are represented as events (milestones with zero duration).
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CThe activity that consumes the maximum time is called a node.
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DLogically and sequentially connected activities and events together form a project network.
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ENone of these.
Answer
Correct Answer: The activity that consumes the maximum time is called a node.
Explanation
Introduction / Context:This question checks foundational terminology in project scheduling (PERT/CPM): what are activities, events/nodes, and how they combine to form a network. Clarity on these definitions prevents modeling errors that lead to wrong schedules and floats.
Given Data / Assumptions:
- Activity represents work that takes time and resources.
- Event (node) marks an instantaneous milestone (start or finish) with zero duration.
- A project network links activities and events in logical order.
- Only one statement is incorrect among the given options.
Concept / Approach:In classic Activity-on-Arrow or Activity-on-Node conventions, activities consume time; events (nodes) do not. The critical activity is the one on the critical path with zero total float, but it is still an activity, not a node. Therefore, any statement that calls an activity a node is incorrect.
Step-by-Step Solution:Check option A: It correctly defines activity as time-consuming work.Check option B: Correct—events mark start/finish points with zero duration.Check option C: Incorrect—nodes are events, not time-consuming activities; the longest activity is not called a node.Check option D: Correct—networks are built from activities and events in sequence.Conclude that C is the incorrect statement.
Verification / Alternative check:Standard references define nodes as milestones and activities as duration-bearing tasks. Critical activities have zero total float but remain activities.
Why Other Options Are Wrong:
- Option A: Correct statement; not wrong.
- Option B: Correct statement; not wrong.
- Option D: Correct statement; not wrong.
- Option E: Invalid because there is an incorrect statement (C).
Common Pitfalls:Calling a long or critical activity a node; confusing instantaneous events with time-consuming activities; mixing AOA and AON terminology without keeping their meanings clear.
Final Answer:The activity that consumes the maximum time is called a node.