UGC NET Questions (Paper – 1)

Statements A, B, C, E and F are all correct, while D is false. Logical equivalence requires mutual entailment, so if p and q are equivalent, each entails the other, but a one-way entailment does not guarantee the reverse. Validity of an argument is defined by the impossibility of true premises with a false conclusion, and equivalence between complex forms can be checked via truth tables or algebraic laws. In UGC NET questions, recognising equivalence often allows candidates to prune options or see that two forms say the same thing.

Option A:
Option A is correct because it includes the proper definitions and relationships between equivalence and entailment and connects them to exam strategy, while excluding D, which overgeneralises from entailment to mutual equivalence. This option thus matches standard logical teaching. It also highlights the importance of equivalence in simplifying reasoning tasks.

Option B:
Option B is incomplete since it omits F, failing to mention how recognising equivalence supports option elimination in multiple-choice questions. While A, B, C and E are true, without F the answer does not fully address the UGC NET context. Therefore A, B, C and E only is not the best choice.

Option C:
Option C is wrong because it drops A and includes only B, C, E and F. Without A, the fundamental definition of logical equivalence in terms of truth values is missing, weakening the conceptual foundation. Hence B, C, E and F only cannot be considered complete.

Option D:
Option D is incorrect as it omits B and includes A, C, E and F only. Without B, the definition of argument validity is not stated, which is central to the question. Thus A, C, E and F only does not gather all the correct statements.

All five statements are correct: truth tables enumerate combinations, test validity via true-premise/false-conclusion rows, identify tautologies by all-true columns, require 2³ = 8 rows for three variables, and underpin many exam solutions even when not drawn.

Option A:
Option A is incomplete because it omits E (implicit exam use).

Option B:
Option B is incomplete because it omits D (8-row fact for three variables).

Option C:
Option C is correct because it includes all true statements (A–E).

Option D:
Option D is incorrect because it omits A (the basic definition of what truth tables do).

Statements A, B, C and E correctly explain how truth tables are used to test validity, while D and F are false. Validity is checked by looking for a counterexample row with true premises and false conclusion, and the absence of such a row shows validity. The number of rows indeed increases exponentially with the number of distinct simple propositions. D is wrong because truth tables work for any finite number of premises, and F is unrealistic about exam expectations, where simpler reasoning is usually sufficient.

Option A:
Option A is incomplete because it omits E, failing to mention the key fact that truth table size grows rapidly with the number of propositions. While A, B and C correctly describe the validity test, they do not fully address the structure of truth tables. Hence this option does not contain all the correct statements.

Option B:
Option B is correct since it brings together the procedural rules for testing validity and the structural observation about row growth, without adding the unrealistic or incorrect claims of D and F. It captures both conceptual understanding and practical awareness. Therefore this option is consistent with how truth tables are taught for UGC NET.

Option C:
Option C is wrong because it includes F, implying that students must always construct very large tables during the exam, which is not expected at Paper 1 level. It also omits C’s explicit statement of the condition for validity. This combination therefore misrepresents both difficulty and method.

Option D:
Option D is incorrect as it includes F and omits A, losing the basic explanation of how truth tables identify invalidity. With F present, it misleads students about exam requirements, and the absence of A leaves out the essential test for counterexamples. Thus B, C, E and F only cannot be the right answer.