UGC NET Questions (Paper – 1)

Statements A, B, C and D correctly summarise standard relationships on the traditional square of opposition, whereas E is false. Contradictory propositions cannot both be true and cannot both be false, and contraries cannot both be true but may both be false. “All S are P” versus “No S are P” are contraries, while “All S are P” versus “Some S are not P” are contradictories. The pair “Some S are P” and “No S are P” are also contradictories, not contraries, making E the only wrong statement.

Option A:
Option A is incorrect because it includes D as wrong along with E, but D accurately states a classic contradictory pair. Treating both D and E as wrong would misrepresent the structure of the square of opposition.

Option B:
Option B is also wrong since it marks C as wrong along with E, even though C correctly identifies “All S are P” and “No S are P” as contraries. C and E only therefore misclassifies a true statement as false.

Option C:
Option C is correct because it isolates E, the misidentified pair of contraries, as the sole incorrect statement and leaves the accurate descriptions in A, B, C and D untouched. This matches standard logic used in UGC NET preparation.

Option D:
Option D is incorrect as it groups C and D with E, thereby wrongly casting doubt on correctly named contrary and contradictory pairs. C, D and E only thus fails to preserve reliable information about AEIO relations.

Contraries are propositions that cannot both be true at the same time but can both be false. On the square of opposition, the universal affirmative 'All S are P' and the universal negative 'No S are P' have this relation. There are circumstances where neither statement holds, making both false. Thus the relationship described in the stem is that of contraries.

Option A:
Option A, contradictories, are pairs of propositions that cannot both be true and cannot both be false; exactly one must be true. This relation holds between A and O or E and I, not between A and E. Therefore contradictories is not correct here.

Option B:
Option B, subcontraries, are propositions that cannot both be false but can both be true, a relation found between I and O propositions. Universal statements do not stand in this relation, so subcontraries cannot be the right answer.

Option C:
Option C, subalterns, refers to pairs where the truth of a universal implies the truth of its corresponding particular, such as A implying I. This is a different relation from the one asked about in the question.

Option D:
Option D is correct because contraries specifically describe the relation between universal affirmative and universal negative propositions on the square of opposition, matching the description in the stem.

In the classical square of opposition, A (universal affirmative: “All S are P”) and O (particular negative: “Some S are not P”) are contradictories. This means they cannot both be true and cannot both be false; exactly one of them must be true at any time. Their truth values always oppose each other. This sharp opposition is what defines the contradictory relation.

Option A:
Option A, A and E, are contraries; they cannot both be true, but they can both be false if, for example, some S are P and some are not.

Option B:
Option B, A and I, stand in a relation of subalternation, where truth can flow from universal to particular, but they are not contradictories.

Option C:
Option C correctly selects A and O as contradictories, and similarly E and I form another contradictory pair in the square.

Option D:
Option D, I and O, are subcontraries; they cannot both be false, but they can both be true, so they are not contradictories.

A universal negative proposition denies that any member of the subject class belongs to the predicate class. Its standard form is "No S are P", and in the traditional scheme it is labelled as an E-type proposition. This combination of universal scope and negative quality fits the description in the stem. Hence it is called a universal negative proposition.

Option A:
Option A, particular negative, is limited in scope to some members of the subject class, as in "Some S are not P". It does not deny membership for all subjects and so cannot represent the form given in the question.

Option B:
Option B is correct because universal negative precisely designates a statement that denies the predicate of every member of the subject class. It is a key category in the square of opposition and contrasts with universal affirmative statements. This alignment makes universal negative the appropriate choice.

Option C:
Option C, universal affirmative, asserts that all members of the subject class belong to the predicate class. It has the opposite quality to the negative proposition described and therefore does not match.

Option D:
Option D, particular affirmative, affirms the predicate for at least one member of the subject class. It is both narrower in scope and positive in quality, which differs from the universal denial described in the stem.

In traditional logic, a universal affirmative proposition asserts that every member of the subject class belongs to the predicate class. It is symbolised as "All S are P" and classified as an A-type proposition on the square of opposition. This structure combines universal quantity with affirmative quality. Therefore the proposition described is correctly termed a universal affirmative.

Option A:
Option A is correct because universal affirmative explicitly captures the idea of a positive assertion about all members of a class. It is distinguished from other categorical forms by its scope over the entire subject class and its affirming character. This matches exactly the form "All S are P" given in the question.

Option B:
Option B, universal negative, denies membership for all subjects in the predicate class, as in "No S are P". It has universal quantity but negative quality, which is not what the stem describes. Thus universal negative is not suitable here.

Option C:
Option C, particular affirmative, asserts that at least one member of the subject class belongs to the predicate class, as in "Some S are P". It does not speak about all members and therefore fails to fit the description.

Option D:
Option D, particular negative, denies the predicate of at least one subject, as in "Some S are not P". It differs in both quantity and quality from the universal affirmative type. Hence particular negative cannot be the correct answer.

Statements A, B, C, D and E correctly summarise the traditional and modern views of the square of opposition, while F is false. The traditional square treats A and E as contraries and I and O as subcontraries, and maintains that contradictory pairs cannot both be true or both be false. Modern logic largely drops contrariety and subcontrariety due to the rejection of existential import, but it keeps the contradictory relations intact. F is wrong because subalternation from universal to particular does not automatically hold under the modern, non-existential reading. Therefore A, B, C, D and E only is the correct combination.

Option A:
Option A is correct because it includes all the true statements and excludes only F, which misstates the scope of subalternation in modern logic. It captures both the traditional structure and the modifications introduced by the Boolean interpretation. This makes it the only option that fully matches accepted logical theory.

Option B:
Option B is incomplete because it omits E, which correctly notes that contradictory relations remain valid in both interpretations. Without E, the description of what survives in the modern view is incomplete. Hence A, B, C and D only does not represent the full set of correct statements.

Option C:
Option C is wrong because it includes F along with B, C, D and E. Including F treats subalternation as always valid in modern logic, which is not the case when universals are not assumed to have existential import. This error makes the combination inconsistent with standard textbook accounts.

Option D:
Option D is incorrect because it leaves out B and E and wrongly includes F. B is needed to characterise subcontraries, and E is needed to show what survives in the modern view. With these omissions and the inclusion of F, A, C, D and F only cannot be accepted as the correct set.

Statements A, B, C and D correctly describe the relations of contrariety and subcontrariety in the traditional square, and F is true about exam usage. E is false because modern logic’s treatment of universal propositions without assumed existential import undermines some of the classical relationships. Thus the correct set of true statements is A, B, C, D and F only.

Option A:
Option A is correct since it includes all the accurate relational claims plus the observation that UGC NET may still use the traditional framework. It excludes E, which overstates the continuity between traditional and modern logic. This makes the option consistent with both history and syllabus.

Option B:
Option B is incomplete, as it omits F and therefore does not mention the exam context. While A, B, C and D are true, the option fails to cover all the correct statements listed.

Option C:
Option C is wrong because it includes E, which incorrectly claims that all traditional relations survive in modern treatment unchanged. This conflicts with standard modern logic texts, so the combination cannot be accepted.

Option D:
Option D is incorrect since it leaves out B, omitting the key general statement about contraries, and thus does not contain all true statements. Consequently, it does not represent the full correct set.

The statement “Some students are diligent” is an existential claim asserting that at least one member of the class of students has the property of being diligent. Its contradictory is “No student is diligent.” Therefore, if “some students are diligent” is true, then the statement “no student is diligent” must be false. Saying “It is not the case that no student is diligent” is logically equivalent to affirming that at least one diligent student exists.

Option A:
Option A is stronger than “some”; it claims that all students are diligent, which need not follow from the existence of at least one diligent student.

Option B:
Option B is the direct negation of the original statement and cannot be true if “some students are diligent” is true.

Option C:
Option C correctly denies the universal negative and is consistent with the existential affirmation about diligent students.

Option D:
Option D narrows the claim to exactly one student, which again is stronger than “some” and does not logically follow.

Statements A, B, D and E are correct, whereas C and F are false. A and B correctly describe the distribution of subject and predicate in universal forms, and D correctly notes that O distributes only the predicate. E is right that A and O are contradictories in the traditional square. C is wrong because I distributes neither term, and F is wrong because modern (Boolean) logic does not usually treat universal statements as existentially loaded. Hence A, B, D and E only is the correct combination.

Option A:
Option A is incomplete because it omits E, which correctly identifies the contradictory relation between A and O. Although A, B and D are true about distribution, leaving out E makes the description of categorical relations less complete. Therefore A, B and D only cannot be accepted as the full set of correct statements.

Option B:
Option B is incorrect as it omits D and claims only A, B and E are correct. While A, B and E are true, ignoring the distribution property of O propositions means one correct statement is missing. As a result, this option does not capture all the true statements given.

Option C:
Option C is wrong because it does not include A and instead accepts B, D and E only. Omitting A removes the basic rule for distribution in A statements. Since A is clearly correct, any option that leaves it out fails to represent the entire set of true statements.

Option D:
Option D is correct because it groups A, B, D and E, all of which align with traditional categorical logic and the square of opposition. It excludes C, which overstates I’s distribution, and F, which misrepresents modern logic’s stance on existential import. Thus this option exactly matches the set of correct statements.

Contradictory propositions are such that one must be true and the other must be false in every possible situation. On the square of opposition, A and O types and E and I types stand in this relation. The defining feature is that they cannot both be true and cannot both be false. Therefore the pair described in the stem are called contradictories.

Option A:
Option A is correct because contradictories exactly capture the mutual exclusivity and exhaustive character mentioned. If one member of a contradictory pair holds, the other must fail, and vice versa. This condition matches the description given in the statement.

Option B:
Option B, contraries, cannot both be true but can both be false, as with "All S are P" and "No S are P". They lack the requirement that one must be true when the other is false. Hence contraries are not the right relation here.

Option C:
Option C, subcontraries, cannot both be false but can both be true, as in "Some S are P" and "Some S are not P". This is the opposite pattern to that described in the question. Therefore subcontraries are not appropriate.

Option D:
Option D, subalterns, involve a relation of implication between universal and particular forms where truth flows downward. They do not exhibit the stringent mutual exclusivity of contradictories. Thus subalterns do not fit the stem.

B is correct: A (“All S are P”) and O (“Some S are not P”) are contradictories. C is correct because contradictories cannot both be true and cannot both be false. E is correct: I and O are subcontraries (they cannot both be false but may both be true). A is false (it describes contraries, not contradictories). D is false because A and E are contraries, not subcontraries. Thus B, C and E only are correct.

Option A:
Option A is incomplete because it omits E, a key relation on the square involving particular propositions.

Option B:
Option B is wrong because it adds D, which misclassifies A and E as subcontraries.

Option C:
Option C is correct because it includes exactly the true relationships and excludes A and D, which are incorrect.

Option D:
Option D is incorrect because it includes A, which misdefines contradictories.