UGC NET Questions (Paper – 1)

Statements D and E are wrong, while A, B, C and F are correct. A and B correctly describe the truth conditions for conjunction and inclusive disjunction, and C accurately symbolises the exclusive “either–or”. F is true because truth tables are standard tools for checking validity. D mistakenly describes a tautology instead of a contradiction, and E wrongly describes the condition for a contingent statement rather than a tautology, so these two are the wrong statements.

Option A:
Option A is incorrect because it singles out only D as wrong and ignores E, which also misrepresents the definition of a tautology. Since both D and E give inverted definitions, treating only one of them as wrong undercounts the errors. Therefore this option does not match the full set of wrong statements.

Option B:
Option B is also incomplete, as it selects only E and ignores D. D is clearly false because a contradiction is never true in any assignment, not always true. By failing to include D, this option again fails to capture all wrong statements listed.

Option C:
Option C is correct because it groups exactly D and E, the two statements that invert the standard meanings of contradiction and tautology. It leaves A, B, C and F untouched, all of which correctly describe truth-functional connectives and the use of truth tables. This combination therefore matches the required set of wrong statements.

Option D:
Option D is wrong because it adds B, which is a correct description of inclusive disjunction, to the set of wrong statements. B rightly states that “p or q” is false only when both p and q are false. Including B beside the genuinely wrong D and E makes the option logically inconsistent.

Meta communication refers to messages about other messages that tell us how to interpret the words. A harsh tone saying "I am not angry" suggests hidden annoyance. The voice quality comments on and partly contradicts the verbal content. Thus it is meta communication.

Option A:
Feedback is the receiver's response,not an aspect of the original message.

Option B:
Redundancy repeats information and does not change its interpretation.

Option C:
Meta communication fits because tone provides an extra “message about the message,” signalling attitude and guiding how the words should be interpreted.

Option D:
Mechanical noise is unintentional interference rather than a meaningful cue about attitude,so it does not fit here.

A contradiction is a statement that is false under every possible assignment of truth values to its variables. The expression P ∧ ¬P asserts that P is both true and not true at the same time, which cannot occur. In any valuation, either P is true or P is false; in neither case can the conjunction of P and its negation be true. Hence this expression is always false and is a standard example of contradiction.

Option A:
Option A directly combines a proposition with its own negation using “and,” ensuring that no scenario makes the whole statement true.

Option B:
Option B, P ∨ ¬P, is actually a tautology, as it is always true regardless of P’s value.

Option C:
Option C can be true or false depending on the values of P and Q, so it is a contingency, not a permanent contradiction.

Option D:
Option D, P → Q, is also contingent; its truth depends on how P and Q are valued.

A contradiction is a statement that cannot be true under any assignment of truth values to its components. Its logical form guarantees falsity in every possible case. Such statements are logically impossible and indicate inconsistency. Therefore the compound statement described in the stem is a contradiction.

Option A:
Option A, tautology, is always true and thus stands opposite to contradiction. It does not match the condition of being false in all valuations. Hence tautology is not the correct answer.

Option B:
Option B, contingency, can be true in some cases and false in others. It lacks the universal falsity required by the stem. Therefore contingency is not appropriate here.

Option C:
Option C, paradox, is an informal term for seemingly self-contradictory statements, but not every paradox is logically false under all valuations. The stem instead describes the technical notion of contradiction. Thus paradox is not the best label.

Option D:
Option D correctly names contradiction as the form that is false in every possible situation. Recognising contradictions is crucial for testing the consistency of logical systems. Hence contradiction is the correct choice.

D and E are wrong because they reverse the meanings of tautology and contingency. A tautology is true in all possible situations, not always false, and a contingent proposition is true in some situations and false in others, not true in all. Statements A and B correctly describe what counts as a statement in logic, and C accurately expresses the idea that contradictory statements cannot both be true simultaneously. Thus the pair D and E only is the correct set of wrong statements.

Option A:
Option A is incorrect because it selects D alone, but E is also wrong; contingent propositions are not true in all possible situations. By ignoring E, Option A fails to identify all the incorrect statements.

Option B:
Option B is also incorrect because it focuses only on E and ignores D, which misdefines tautology as always false. Since both D and E are wrong, singling out only one of them does not satisfy the requirement of the question.

Option C:
Option C is correct because it groups together D and E, the two statements that misrepresent the key logical categories of tautology and contingency. It leaves A, B and C untouched, acknowledging that they are true characterisations of statements and contradictions.

Option D:
Option D is wrong because it includes C, which is actually true: contradictory statements cannot both be true at the same time. By treating C as if it were wrong along with D, this option misidentifies the logical property of contradiction.

A tautology is a compound proposition that evaluates to true under every possible assignment of truth values to its component propositions. It is logically true by virtue of its form rather than specific factual content. In a full truth table, the column for a tautology’s final result contains only Ts and no Fs. Because of this feature, tautologies play an important role in testing argument forms and deriving equivalences.

Option A:
Option A matches the formal definition of a tautology as a statement that never turns out false in any row of its truth table. It captures the idea of logical necessity independent of empirical facts.

Option B:
Option B describes a contradiction, which is always false and has only Fs in its truth table, the exact opposite of a tautology.

Option C:
Option C refers to a contingency, which is true on some valuations and false on others, so it is neither tautological nor contradictory.

Option D:
Option D suggests that the statement cannot be tested, which is incorrect because tautologies are routinely checked using truth tables and formal methods.

Statements A and B restate De Morgan’s laws, showing how negation distributes over “and” and “or”, C correctly defines logical equivalence in terms of matching truth values and D is true because De Morgan’s laws explicitly connect conjunction, disjunction and negation. Statement E is false since contradictory statements cannot both be true in any possible situation; one must be false whenever the other is true. Hence, the combination A, B, C and D only is correct.

Option A:
Option A is incomplete because, although it lists three true statements, it omits D and thus does not explicitly say that De Morgan’s laws are the ones relating “and”, “or” and “not”. Without D, the named connection between these operators is not emphasised.

Option B:
Option B is also incomplete because it leaves out A and thereby fails to include the first De Morgan equivalence concerning the negation of “p and q”. That omission makes the description of the laws partial.

Option C:
Option C is correct as it bundles all four true statements, fully describing De Morgan’s laws and logical equivalence, while rejecting E, which mischaracterises contradictions. It aligns with the logical tools used in UGC NET reasoning.

Option D:
Option D is wrong because it includes E, the false statement about contradictions, and omits C, the formal definition of logical equivalence. This combination mixes error with omission.

Statements A, B and C correctly define tautology, contradiction and contingency by looking at truth across all valuations. Statement E is also true because the negation of a formula that is always true must be false on every valuation, hence a contradiction. Statement D is impossible in classical logic, since no statement can be both always true and always false at once. Therefore, the complete set of correct statements is A, B, C and E only, which matches option C.

Option A:
Option A is incomplete because it omits E and therefore fails to mention the important relationship between tautologies and contradictions via negation. It lists correct information but not the full set of true statements for this question.

Option B:
Option B is incorrect since it leaves out B and includes only A, C and E, ignoring the explicit definition of contradiction that is central to the topic. Without B the description of the three categories is not complete.

Option C:
Option C is correct as it brings together the accurate definitions of the three types of statements and the fact that the negation of a tautology is a contradiction, while excluding D, which suggests an incoherent situation in classical logic.

Option D:
Option D is wrong because it includes D, which falsely claims that a statement can be both tautology and contradiction and calls that “contingent”, and it omits A, so it both accepts a logical impossibility and loses a key correct statement.

A contradiction is a statement that cannot be true in any possible situation because its form guarantees falsity on every line of its truth table. It is logically inconsistent and unsatisfiable, meaning no assignment of truth values makes it hold. Such statements often arise from combining a claim and its negation. Therefore the statement described in the stem is accurately called a contradiction.

Option A:
Option A is correct because contradictions exhibit the extreme case of logical falsity: they are false in all possible worlds or under all valuations. Recognising contradictions is important in proofs by contradiction and in detecting inconsistent sets of premises.

Option B:
Option B, tautology, is the exact opposite: a statement that is true under every possible assignment of truth values. While it also has a uniform truth-value pattern, that pattern is truth rather than falsehood.

Option C:
Option C, contingency, is true under some assignments and false under others, which is the normal status of most factual claims. The stem, however, speaks of a statement that is false in every possible case.

Option D:
Option D, hypothesis, refers to a provisional assumption or conjecture and does not specify a particular truth-table pattern. A hypothesis could be a tautology, contradiction or contingency depending on its logical form and content.

Statements A and B correctly define tautology and contradiction, D states that truth tables are a systematic method to classify statements and E rightly explains that contingent statements are sometimes true and sometimes false. Statement C is false because it mistakenly assigns the property of tautology to contingent statements by saying they are true in all situations. Consequently, A, B, D and E together form the only correct combination.

Option A:
Option A is correct because it lists exactly the statements that match standard logical definitions and excludes C, which confuses contingency with tautology. It reflects the approach used in UGC NET when analysing compound statements.

Option B:
Option B is incomplete since it omits E and therefore does not describe how contingent statements behave across different truth assignments. Without E, the classification of logical status is less complete.

Option C:
Option C is wrong because it leaves out A and thereby fails to define tautology explicitly, while still not correcting the misstatement about contingency. Although some included statements are true, the set is not complete.

Option D:
Option D is incorrect because it includes C, the false description of contingent statements, and so mixes an error with otherwise true statements. That mixture makes the option logically inconsistent.

Statements A, B, D and E are correct, while C is false. A tautology is true under every valuation and a contradiction is false under every valuation. A contingent statement is true in some valuations and false in others, so C is incorrect. If a conclusion is a tautology, there is no possible case where premises are true and the conclusion is false, so the argument is valid regardless of premises (though it may be uninformative). Distinguishing these notions helps in validity checking in UGC NET, so E is also correct.

Option A:
Option A is incorrect because it omits D. Since D is true in classical logic, A, B, E only is incomplete.

Option B:
Option B is correct because it includes exactly the true statements A, B, D and E and excludes C, which misdefines contingency.

Option C:
Option C is wrong because it includes C, the false claim that a contingent statement is true in all valuations.

Option D:
Option D is wrong because it includes C (false) and omits B (true), so A, C, D, E only cannot be correct.

Statements A, B, C, E and F correctly distinguish tautologies, contradictions and contingencies and relate them to argument validity, while D is false. A tautological conclusion is always true, so any argument with such a conclusion is at least logically valid, though possibly uninformative. Contradictory premises render an argument vacuously valid because there is no case where all premises are true, and recognising logical status helps in judging equivalence and validity in exams. D is wrong because it asserts the opposite about tautological conclusions. Therefore A, B, C, E and F only is the correct combination.

Option A:
Option A is incomplete because it omits E and F, leaving out the role of contradictory premises and the exam-related significance of these distinctions. Although A, B and C are true definitions, they do not connect to argument validity. Thus this option is not complete.

Option B:
Option B is also incomplete, adding E but still omitting F, which summarises the practical usefulness of these categories in UGC NET. Without F, the option lacks an explicit link to reasoning tasks. Hence it cannot be the best answer.

Option C:
Option C is correct since it combines the basic definitions with a key fact about arguments from contradictions and the exam relevance of recognising logical status. It excludes D, which mischaracterises arguments with tautological conclusions. This makes the option logically consistent.

Option D:
Option D is incorrect because it includes D, thereby accepting the false view that tautological conclusions always make arguments invalid, and it omits A, the central definition of tautology. This combination cannot be taken as correct.

All five statements A through E are correct descriptions of standard logical classifications and their exam use. Tautologies are true under all assignments, contradictions are always false, and contingencies vary with the assignment. A statement and its negation cannot both be tautologies because their truth-values must differ somewhere. Recognising tautological patterns is useful in UGC NET for spotting valid argument forms.

Option A:
Option A is incomplete because it omits E, missing the applied exam-use point.

Option B:
Option B is correct since it includes every true statement (A–E).

Option C:
Option C is wrong because it omits C (definition of contingency).

Option D:
Option D is incorrect because it omits A (definition of tautology).

Statements A, B and C provide the standard classification of formulas into tautology, contradiction and contingency. Statement E is also true because truth tables are a systematic way to test which of these categories a formula falls into. Statement D is false because the existence of contingencies means there is indeed a third kind of formula. Therefore, A, B, C and E only make up the correct set.

Option A:
Option A is incomplete as it omits E and thus does not mention the main procedural tool, the truth table, which is central to exam questions on this topic.

Option B:
Option B is wrong since it includes D, which denies the existence of contingencies, contradicting statement C.

Option C:
Option C is correct because it captures all true statements and excludes D, which misclassifies propositional forms.

Option D:
Option D is incorrect as it retains D and omits A, losing the definition of tautology while including a false generalisation about all formulas.

A set of statements is inconsistent if they cannot all be true at the same time. Saying “Some teachers are strict” asserts the existence of at least one strict teacher. Saying “No teacher is strict” denies that any teacher is strict. These two claims cannot both be true together; if one is true, the other must be false. Hence, this pair is logically inconsistent.

Option A:
Option A’s two statements are compatible, because if all poets are imaginative, then certainly some poets are imaginative, so both can be true together.

Option B:
Option B directly pits an existential claim against a universal negative about the same property, creating a clear contradiction.

Option C:
Option C is consistent because if all birds can fly and penguins are birds, it follows that penguins can fly within that system, even if this conflicts with real world facts.

Option D:
Option D is also consistent, allowing for a mixed group of scientists, some honest and some not, which poses no logical problem.