Explore topic-wise MCQs in Discrete Mathematics.

This section includes 91 Mcqs, each offering curated multiple-choice questions to sharpen your Discrete Mathematics knowledge and support exam preparation. Choose a topic below to get started.

51.

An isomorphism of a group onto itself is called ____________

A. homomorphism
B. heteromorphism
C. epimorphism
D. automorphism
Answer» E.
52.

A finite group G of order 219 is __________

A. a semigroup
B. a subgroup
C. a commutative inverse
D. a cyclic group
Answer» E.
53.

__________ is not necessarily a property of a Group.

A. Commutativity
B. Existence of inverse for every element
C. Existence of Identity
D. Associativity
Answer» B. Existence of inverse for every element
54.

Suppose P(h) is a group of permutations and identity permutation(id) belongs to P(c). If ϕ(c)=c then which of the following is true?

A. ϕ∈P(h)
B. ϕ⁻¹∈P(h)
C. ϕ⁻²∈P(h)
D. None of the mentioned
Answer» C. ϕ⁻²∈P(h)
55.

A group of rational numbers is an example of __________

A. a subgroup of a group of integers
B. a subgroup of a group of real numbers
C. a subgroup of a group of irrational numbers
D. a subgroup of a group of complex numbers
Answer» C. a subgroup of a group of irrational numbers
56.

Suppose (2, 5, 8, 4) and (3, 6) are the two permutation groups that form cycles. What type of permutation is this?

A. odd
B. even
C. acyclic
D. prime
Answer» C. acyclic
57.

An identity element of a group has ______ element.

A. associative
B. commutative
C. inverse
D. homomorphic
Answer» D. homomorphic
58.

__________ matrices do not have multiplicative inverses.

A. non-singular
B. singular
C. triangular
D. inverse
Answer» C. triangular
59.

If A, B, and C are invertible matrices, the expression (AB⁻¹)⁻¹(CA⁻¹)⁻¹C2 evaluates to ____________

A. BC
B. C⁻¹BC
C. AB⁻¹
D. C⁻¹B
Answer» B. C⁻¹BC
60.

The set of odd and even positive integers closed under multiplication is ________

A. a free semigroup of (M, ×)
B. a subsemigroup of (M, ×)
C. a semigroup of (M, ×)
D. a subgroup of (M, ×)
Answer» C. a semigroup of (M, ×)
61.

Let * be the binary operation on the rational number given by a*b=a+b+ab. Which of the following property does not exist for the group?

A. closure property
B. identity property
C. symmetric property
D. associative property
Answer» C. symmetric property
62.

How many different non-isomorphic Abelian groups of order 8 are there?

A. 5
B. 4
C. 2
D. 3
Answer» D. 3
63.

Consider the binary operations on X, a*b = a+b+4, for a, b ∈ X. It satisfies the properties of _______

A. abelian group
B. semigroup
C. multiplicative group
D. isomorphic group
Answer» B. semigroup
64.

Two groups are isomorphic if and only if __________ is existed between them.

A. homomorphism
B. endomorphism
C. isomorphism
D. association
Answer» D. association
65.

The elements of a vector space form a/an ____________ under vector addition.

A. abelian group
B. commutative group
C. associative group
D. semigroup
Answer» B. commutative group
66.

The set of rational numbers form an abelian group under _________

A. Association
B. Closure
C. Multiplication
D. Addition
Answer» D. Addition
67.

The Number of Elements Satisfying g7=e in a finite Group F is ______

A. even
B. not a number
C. odd
D. rational
Answer» D. rational
68.

If x * y = x + y + xy then (G, *) is _____________

A. Monoid
B. Abelian group
C. Commutative semigroup
D. Cyclic group
Answer» D. Cyclic group
69.

If 54th row of a 67th row matrix is linearly independent with each other then find the rank of the matrix.

A. 61
B. 54
C. 187
D. 32
Answer» C. 187
70.

A relation (34 × 78) × 57 = 57 × (78 × 34) can have __________ property.

A. distributive
B. associative
C. commutative
D. closure
Answer» C. commutative
71.

__________ are called group postulates.

A. Group lemmas
B. Group theories
C. Group axioms
D. Group
Answer» D. Group
72.

Invariant permutations of two functions can form __________

A. groups
B. lattices
C. graphs
D. rings
Answer» B. lattices
73.

Let (A7, ⊗7)=({1, 2, 3, 4, 5, 6}, ⊗7) is a group. It has two sub groups X and Y. X={1, 3, 6}, Y={2, 3, 5}. What is the order of union of subgroups?

A. 65
B. 5
C. 32
D. 18
Answer» C. 32
74.

If group G has 65 elements and it has two subgroups namely K and L with order 14 and 30. What can be order of K intersection L?

A. 10
B. 42
C. 5
D. 35
Answer» D. 35
75.

Let M be an 4×4 matrix with real entries such that Mᵏ=0, for some k≥1. Find the determinant value of (I+M), where, I be the 4 x 4 identity matrix.

A. 72
B. 1
C. 4
D. 36
Answer» C. 4
76.

If we take a collection of {∅, {2}, {3}, {5}} ordered by inclusion. Which of the following is true?

A. isomorphic graph
B. poset
C. lattice
D. partially ordered set
Answer» C. lattice
77.

Which of the following is not an abelian group?

A. semigroup
B. dihedral group
C. trihedral group
D. polynomial group
Answer» C. trihedral group
78.

Intersection of subgroups is a ___________

A. group
B. subgroup
C. semigroup
D. cyclic group
Answer» C. semigroup
79.

A group G of order 20 is __________

A. solvable
B. unsolvable
C. 1
D. not determined
Answer» B. unsolvable
80.

An element a in a monoid is called an idempotent if ______________

A. a⁻¹=a*a⁻¹
B. a*a²=a
C. a²=a*a=a
D. a³=a*a
Answer» D. a³=a*a
81.

___________ are the symmetry groups used in the Standard model.

A. lie groups
B. subgroups
C. cyclic groups
D. poincare groups
Answer» B. subgroups
82.

Matrix multiplication is a/an _________ property.

A. Commutative
B. Associative
C. Additive
D. Disjunctive
Answer» C. Additive
83.

A group (M,*) is said to be abelian if ___________

A. (x+y)=(y+x)
B. (x*y)=(y*x)
C. (x+y)=x
D. (y*x)=(x+y)
Answer» C. (x+y)=x
84.

A cyclic group is always _________

A. abelian group
B. monoid
C. semigroup
D. subgroup
Answer» B. monoid
85.

How many properties can be held by a group?

A. 2
B. 3
C. 5
D. 4
Answer» D. 4
86.

{1, i, -i, -1} is __________

A. semigroup
B. subgroup
C. cyclic group
D. abelian group
Answer» D. abelian group
87.

An algebraic structure _________ is called a semigroup.

A. (P, *)
B. (Q, +, *)
C. (P, +)
D. (+, *)
Answer» B. (Q, +, *)
88.

A non empty set A is termed as an algebraic structure ________

A. with respect to binary operation *
B. with respect to ternary operation ?
C. with respect to binary operation +
D. with respect to unary operation –
Answer» B. with respect to ternary operation ?
89.

A cyclic group can be generated by a/an ________ element.

A. singular
B. non-singular
C. inverse
D. multiplicative
Answer» B. non-singular
90.

A monoid is called a group if _______

A. (a*a)=a=(a+c)
B. (a*c)=(a+c)
C. (a+c)=a
D. (a*c)=(c*a)=e
Answer» E.
91.

Condition for monoid is __________

A. (a+e)=a
B. (a*e)=(a+e)
C. a=(a*(a+e)
D. (a*e)=(e*a)=a
Answer» E.