UGC NET Questions (Paper – 1)

Venn diagrams use overlapping circles to represent classes and their intersections. In syllogistic reasoning they visually display how subject and predicate classes relate. This makes it easier to test whether a syllogism’s conclusion follows from its premises. Therefore the method described in the stem is called a Venn diagram.

Option A:
Option A correctly identifies the overlapping circle diagrams as Venn diagrams. These diagrams provide a standard visual tool in elementary logic. Hence this option directly fits the description.

Option B:
Option B, flow chart, shows sequences of steps in a process rather than class relationships. It is commonly used in algorithm design, not in testing syllogistic validity. Thus flow chart is not the right answer here.

Option C:
Option C, network diagram, typically represents nodes and connections such as in communication or social networks. It does not conventionally illustrate logical class relations. Therefore network diagram does not match the logical use in the question.

Option D:
Option D, tree diagram, is often used to represent branching possibilities or hierarchical structures. While useful in some areas of logic, it is not the standard representation of class inclusion by overlapping regions. Hence tree diagram is not correct.

From the statement “All researchers are readers,” we know that every researcher belongs to the larger class of readers. Assuming the class of researchers is non-empty (as in classical categorical logic), this implies that at least one reader is also a researcher, so it is safe to say some readers are researchers. The information about some readers being teachers does not change this basic inclusion.

Option A:
Option A stays within the clear consequence of putting all researchers inside the set of readers: if there are any researchers, then some readers are researchers.

Option B:
Option B would require that some of the readers who are teachers are also researchers, which is not given by the premises and may or may not be true.

Option C:
Option C overstates the relationship by claiming that all researchers are teachers, which is nowhere implied.

Option D:
Option D introduces a particular negative about researchers and teachers without support in the premises, so it goes beyond the logical information available.

Venn diagrams use overlapping circles to depict the relationships between classes such as inclusion, exclusion and intersection. In testing syllogisms, they visually show whether the logical requirements of the premises allow the conclusion. This graphical method provides an intuitive way to evaluate validity. Hence the diagrams mentioned in the stem are called Venn diagrams.

Option A:
Option A, flow charts, represent sequences of steps or decisions in procedures rather than set relationships in logic. They are used more in computer science and process modelling than in categorical reasoning. Thus flow charts are not the correct answer.

Option B:
Option B is correct because Venn diagrams are specifically designed to portray the logical structure of categorical propositions. By shading or marking regions, we can see how premises constrain possible cases and assess whether the conclusion follows. This matches the description provided.

Option C:
Option C, decision trees, represent branching choices and consequences and are often used in decision analysis, not in standard testing of syllogistic relations between classes. Therefore decision trees do not fit the stem.

Option D:
Option D, network graphs, depict nodes and connections for relationships like communication or social ties. They are not the conventional tool for illustrating class inclusion in traditional logic. Hence network graphs are not appropriate here.