Artificial Intelligence MCQs - Knowledge Representation and Logic (Set 5)

Q1. A propositional sentence that is true in every possible model is called:

a) satisfiable

b) valid (a tautology)

c) contingent

d) unsatisfiable

Q2. Which inference rule derives Q from the premises P and P => Q?

a) Modus tollens

b) And-elimination

c) Resolution with a unit clause only

d) Modus ponens

Q3. The implication P => Q is logically equivalent to which sentence?

a) not P or Q

b) P or not Q

c) not P and Q

d) Q => P

Q4. Which sentence is the contrapositive of P => Q, and therefore equivalent to it?

a) Q => P

b) not P => not Q

c) not Q => not P

d) P => not Q

Q5. What is the conjunctive normal form (CNF) of the biconditional A <=> B?

a) (A or B) and (not A or not B)

b) (not A or B) and (not B or A)

c) (A and B) or (not A and not B)

d) (not A or B) and (A or B)

Q6. What is the resolvent of the clauses (P or Q) and (not Q or R)?

a) P or Q or R

b) P and R

c) Q or R

d) P or R

Q7. To prove KB entails alpha by resolution refutation, one shows that:

a) KB and not alpha is unsatisfiable, deriving the empty clause

b) KB and alpha is satisfiable

c) alpha alone is valid

d) not KB and alpha is unsatisfiable

Q8. What is the most general unifier of Knows(John, x) and Knows(y, Mother(y))?

a) {x/John, y/Mother(John)}

b) {y/x, x/John}

c) {y/John, x/Mother(John)}

d) The terms do not unify

Q9. Why do P(x, x) and P(Alice, Bob) fail to unify, where Alice and Bob are distinct constants?

a) Constants can never appear in a unifier

b) x would need to equal both Alice and Bob at once

c) The predicates have different arities

d) The occurs check fails

Q10. Unifying the variable x with the term F(x) fails because of the:

a) frame problem

b) closed-world assumption

c) qualification problem

d) occurs check

Q11. Which statement correctly contrasts forward and backward chaining?

a) Forward chaining is data-driven, starting from known facts; backward chaining is goal-driven, working back from the query

b) Forward chaining works only in first-order logic; backward chaining only in propositional logic

c) Both are goal-driven but differ in rule ordering

d) Forward chaining is incomplete for Horn clauses while backward chaining is complete

Q12. A Horn clause is a disjunction of literals with:

a) exactly two positive literals

b) no negative literals

c) at most one positive literal

d) at least one positive literal

Q13. Which first-order sentence correctly expresses 'Every student likes some course'?

a) Exists y for all x: Student(x) and Course(y) and Likes(x, y)

b) For all x: Student(x) => (Exists y: Course(y) and Likes(x, y))

c) For all x: Student(x) and (Exists y: Course(y) => Likes(x, y))

d) Exists x: Student(x) => (For all y: Course(y) and Likes(x, y))

Q14. Which translation of 'Some king is wise' is correct?

a) For all x: King(x) => Wise(x)

b) Exists x: King(x) => Wise(x)

c) For all x: King(x) and Wise(x)

d) Exists x: King(x) and Wise(x)

Q15. What is the Skolemised form of For all x Exists y Loves(x, y)?

a) For all x Loves(x, F(x))

b) For all x Loves(x, C)

c) Loves(C, F(C))

d) Exists y Loves(y, y)

Q16. In a semantic network, which kind of link mainly supports inheritance of properties from a category to its members and subcategories?

a) Part-of link

b) Causal link

c) IS-A (subset/member) link

d) Temporal link

Q17. In Minsky's frame-based representation, knowledge about a stereotyped object is stored as:

a) a set of clauses in conjunctive normal form

b) slots with fillers, which may include default values and attached procedures

c) a probability table for each attribute

d) a sequence of production rules only

Q18. Over the propositional symbols A, B and C, how many models satisfy (A or B) and not C?

a) 3

b) 2

c) 4

d) 6