Maths MCQ Class 12 Ch-1 | Relations & Functions

 Mathematics

Multiple Choice Questions (MCQ)
MCQ | Class 12 | Chapter 1
RELATIONS AND FUNCTIONS

  • MCQ Based on the different types of relations
  • MCQ  Based on the different types of functions
  • MCQ Based on the Domain and Range of the functions.
  • MCQ Based on the general problems based of relations and functions.
  • MCQ Based from the CBSE Sample Questions

Features

  • In this pdf given below you find the important MCQ which are strictly according to the CBSE syllabus and are very useful for the CBSE Examinations. 
  • Solution Hints are also given to some difficult problems. 
  • Each MCQ contains four options from which one option is correct. 
  • On the right hand side column of the pdf Answer option is given.

Action Plan

  • First of all students should Learn and write all basic points and Formulas related to the Relations and Functions.
  • Start solving  the NCERT Problems with examples.
  • Solve the important assignments on the Relations and Functions.
  • Then start solving the following MCQ.

MCQ | CHAPTER 1 | CLASS 12

RELATIONS AND FUNCTIONS

Q 1) Which of these is not a type of relation?
a) Reflexive
b) Surjective
c) Symmetric
d) Transitive 

Ans: b

Q 2) A relation is a set of all
a) Ordered pairs
b) Functions
c) y – values
d) None of these 
Ans: a
Q 3) Let A = { x1, x2, x3, ……..xm}, B = {
y1, y2, y3,……..yn}
, then the total number of non empty relations that can be defined from A to B is

a) mn – 1
b) nm – 1
c) mn – 1

d) 2nm – 1
 Ans: d

Q 4) Which of the following relations is symmetric but neither reflexive nor transitive for a set A = {1, 2, 3}.
a) R = {(1, 2), (1, 3), (1, 4)}
b) R = {(1, 2), (2, 1)}
c) R = {(1, 1), (2, 2), (3, 3)}
d) R = {(1, 1), (1, 2), (2, 3)} 

Ans: b

Q 5) Let A = {1,2.3} and consider the relation R = { (1, 1), (2, 2), (3, 3), (1, 2)}, then R is
a) Reflexive but not symmetric
b) Reflexive but not transitive
c) Symmetric and transitive
d) Neither symmetric nor transitive 
Ans: a

Q 6) Which of the following relations is transitive but not reflexive for the set S = {3, 4, 6}?
a) R = {(3, 4), (4, 6), (3, 6)}
b) R = {(1, 2), (1, 3), (1, 4)}
c) R = {(3, 3), (4, 4), (6, 6)}
d) R = {(3, 4), (4, 3)} 
Ans: a

Q 7) Let A = {1, 2, 3, 4} and let R be a relation on A given by
R = {(1, 1), (2, 2), (3, 3), (4, 4), (1, 2), (1, 3), (3, 2)} then
a) R is reflexive, symmetric but not transitive.
b) R is reflexive , transitive but not symmetric
c) R is symmetric, transitive but not reflexive
d) R is equivalence relation 
Ans: b

Q 8) Let R be a relation in the set N given by R={(a, b) : a + b = 5, b > 1}. Which of the following will satisfy the given relation?
a) (2, 3) ∈ R
b) (4, 2) ∈ R
c) (2, 1) ∈ R
d) (5, 0) ∈ R 
Ans: a

Q 9) Let A = { 1, 2, 3} and R be a relation defined on A given by R = {(1, 3), (3,1), (3, 3)} then
a) R is symmetric and reflexive
b) R is symmetric and transitive
c) R is symmetric but not reflexive
d) R is reflexive and transitive 
Ans: c
Q 10) Which of the following relations is reflexive and transitive for the set T = {7, 8, 9}?
a) R = {(7, 7), (8, 8), (9, 9)}
b) R = {(7, 8), (8, 7), (8, 9)}
c) R = {0}
d) R = {(7, 8), (8, 8), (8, 9)} 
Ans: a

Q 11) Let A = {1, 2, 3} and R = A X A, then
a) R is not Symmetric
b) R is not reflexive
c) R is not transitive
d) R is an equivalence relation 
Ans: d

Q 12) Let I be a set of all lines in a XY plane and R be a relation in I defined as R = {(I1, I2) : I1 is parallel to I2}.
What is the type of given relation?

a) Reflexive relation
b) Transitive relation
c) Symmetric relation
d) Equivalence relation 
Ans: d

Q 13) Let R be a relation on the set N be defined by {(x, y) : x, y ∈ N, 2x + y = 41}. Then R is
a) Reflexive
b) Symmetric
c) Transitive
d) None of these
Ans: d
Solution Hint
2x + y = 41
Putting x = y = 1 we get 3 ≠ 41 ⇒ (1, 1) ∉ R ⇒ R is not reflexive
(1, 39) ∈ R but (39, 1) ∉ R ⇒ R is not symmetric 

(18, 5) ∈ R and (5,31) ∈ R but (18,31) ∉ R ⇒ R is not transitive
Q 14)  (a, a) ∈ R, for every a ∈ A. This condition is for which of the following relations?
a) Reflexive relation
b) Symmetric relation
c) Equivalence relation
d) Transitive relation 
Ans: a

Q 15) Domain of   is
a) (-∞ , 2)
b) (2, ∞)
c) (- ∞ , ∞ )
d) None of these 
Ans: a

Q 16) (a1, a2) R
implies that (a2, a1)
R,
for all a1, a2
A. This condition is for which of the following relations?
a) Equivalence relation
b) Reflexive relation
c) Symmetric relation
d) Universal relation 
Ans: c

Q 17) A function f ∶ N→N is defined by f(x)=x2 + 12. What is the type of function here?
a) bijective
b) surjective
c) injective
d) neither surjective nor injective 
Ans: c

Q 18) The following figure depicts which type of function?

a) one-one
b) onto
c) many-one
d) both one-one and onto 
Ans: a

Q 19) The following figure represents which type of function?

a) one-one
b) onto and many one
c) many-one bur not one-one
d) neither one-one nor onto 
Ans: b

Q 20) The domain of    is
a) [1, 8]
b) (-8, 8)
c) [1, 8)
d) (1, 8) 
Ans: a



Q 21) Let R be a relation on N defined by x + 2y = 8. The domain of R is
a) {2, 4, 8}
b) {2, 4, 6, 8}
c) {2, 4, 6}
d) { 1, 2, 3, 4} 

Ans: c

Q 22) The domain of definition of the function y = f(x) =     is
a) (0, ∞)
b)[0, ∞)
c) (-∞ ,0)
d) (-∞ ,0] 
Ans: d
Q 23) A function f : R→R is defined by f(x)= 5x2 – 8. The type of function is
a) one –one
b) onto
c) many-one
d) both one-one and onto 
Ans: c

Q 24) The domain of the function y = f(x) =   is

a) (0, ∞ )
b) (1, ∞)
c) (0,1)
d (- ∞, 1) 
Ans: b
Q 25) The following figure depicts which type of function?
a) injective
b) bijective
c) surjective
d) neither injective nor surjective
Ans: b
Solution Hint 
 The given function is bijective i.e. both one-one and onto.
one – one : Every element in the domain X has a distinct image in the co-domain Y. Thus, the given function is one- one.
onto: Every element in the co- domain Y has a pre- image in the domain X. Thus, the given function is onto.
Q 26) Let A = {1, 2, 3} and B = {4, 5, 6}. Which one of the following functions is bijective?
a) f = {(2, 4), (2, 5), (2, 6)}
b) f = {(1, 5), (2, 4), (3, 4)}
c) f = {(1, 4), (1, 5), (1, 6)}
d) f = {(1, 4), (2, 5), (3, 6)} 
Ans: d

Q 27) The domain of the function f(x)= log(1-x) +   is
a) [-1, 1]
b) (1, ∞)
c) (0, 1)
d(- ∞, -1] 
Ans: d
Q 28) Let P = {10, 20, 30} and Q = {5, 10, 15, 20}. Which one of the following functions is one – one and not onto?
a) f = {(10, 5), (10, 10), (10, 15), (10, 20)}
b) f = {(10, 5), (20, 10), (30, 15)}
c) f = {(20, 5), (20, 10), (30, 10)}
d) f = {(10, 5), (10, 10), (20, 15), (30, 20)} 
Ans: b

Q 29) The domain of the function f(x) =   is
a) R –{2}
b) R
c) R – {0}
d) R – {-2} 
Ans: d

Q 30) Domain of    is
a) [0,4]
b) (0,4)
c) R- (0,4)
d) R- [0,4] 
Ans: a

Q 31) Let M = {5, 6, 7, 8} and N = {3, 4, 9, 10}. Which one of the following functions is neither one-one nor onto?
a) f ={(5, 3), (5, 4), (6, 4), (8, 9)}
b) f = {(5, 3), (6, 4), (7, 9), (8, 10)}
c) f = {(5, 4), (5, 9), (6, 3), (7, 10), (8, 10)}
d) f = {(6, 4), (7, 3), (7, 9), (8, 10)} 

Ans: a

Q 32) The domain of definition of the function f(x) = Log|x| is given by
a) x ≠0
b) x >0
c) x<0
d) x ∈ R 

Ans: a

Q 33) If a relation R on the set {1,2,3} be defined by R = {(1,2)} then R is
a) Transitive
b) None of these
c) Reflexive
d) Symmetric 

Ans: a

Q 34) The range of f(x) =   is

a) 1
b) -1
c) {1}
d {-1} 
Ans: d

Q 35) The range of the function f(x) = |x-1| is
a) (-∞ ,∞)

b) (0, ∞)
c) [0, ∞)
d (- ∞, 0) 
Ans: c

Q 36) The range of the function f(x) =   is

a) (0,3)
b) [0,3)
c) (0,3)
d) [0,3] 
Ans: d

Q 37) The function R : R → R defined by f(x) = 3 – 4x is
a) Onto
b) Not onto
c) Not one – one
d) None of these 

Ans: a

Q 38) The function f : A → B defined by f(x) = 4x + 7, x ∈ R is
(a) one-one
(b) Many-one
(c) Odd
(d) Even 

Ans: a

Q 39) The greatest integer function f(x) = [x] is
(a) One-one
b) Many-one
(c) Both (a) & (b)
d) None of these 

Ans: b

Q 40)   
The number of bijective functions from set A to itself when A contains 72 elements is
(a) 72
(b) (72)2
(c) 72!
(d) 272 

Ans: c

Q 41) Which of the following functions from Z into Z is bijective?
(a) f(x) = x3
(b) f(x) = x + 2
(c) f(x) = 2x + 1
(d) f(x) = x2 + 1 

Ans: b

Q 42) The maximum number of equivalence relations on the set A = {1, 2, 3} are
(a) 1
(b) 2
(c) 3
(d) 5 
Ans: d

Q 43) Total number of equivalence relations defined in the set S = {a, b, c} is
(a) 5
(b) 3!
(c) 23
(d) 33 
Ans: a

Q 44) The function f : R → R given by f(x) = x3 – 1 is
(a) a one-one function
(b) an onto function
(c) a bijection
(d) neither one-one nor onto 
Ans: c

Q 45) Let f : R → R be a function defined by f(x) = x3 + 4, then f is
(a) injective
(b) surjective
(c) bijective
(d) none of these 
Ans: c

Q 46) Given set A = {a, b, c). An identity relation in set A is
(a) R = {(a, b), (a, c)}
(b) R = {(a, a), (b, b), (c, c)}
(c) R = {(a, a), (b, b), (c, c), (a, c)}
(d) R= {(c, a), (b, a), (a, a)}
Ans: b 
Reason: A relation R is an identity relation in set A if for all a ∈ A, (a, a) ∈ R.
Q 47) Set A has 3 elements and the set B has 4 elements. Then the number of injective functions that can be defined from set A to set B is
(a) 144
(b) 12
(c) 24
(d) 64
Ans: c 
Reason: Total injective mappings/functions = 4P3 = 4! = 24.

Q 48) Let A = {a, b }. Then number of one-one functions from A to A possible are
(a) 2
(b) 4
(c) 1
(d) 3
Ans: a
Reason: if n(A) = m, then possible one-one functions from A to A are m!

Q 49) If A = {1, 2, 3} and relation R = {(2, 3)} in A. Then Relation R is
a) Reflexive,
b) Symmetric
c) Transitive.
d) None of these
Ans: c
Reason: Not reflexive, as (1, 1) ∉ R.
Not symmetric, as (2, 3) ∈ R but (3, 2) ∉ R.
This relation is Transitive, Because: Relation R in a non empty set containing one element is transitive.

Q 50) Let A = {1, 2, 3, 4} and B = {a, b, c}. Then number of one-one functions from A to B are
a) 12
b) 4
c) 0
d) None of these
Ans: c 
Reason: Ans 0, Because n(A) > n(B)
Q 51) If n(A) = p, then number of bijective functions from set A to A are
a) p2
b) p!
c) 2p
d) 2p
Ans: b 
Reason: Because If n(A) = p and n(A) = n(B) then the number of bijective functions from A to B is p!
Q 52) Let R be the relation in the set N given by R = {(a, b) : a = b – 2, b > 6}.
a) (2, 4) ∊ R
b) (3, 8) ∊ R
c) (6, 8) ∊  R
d) (8, 7) ∊ R 
Ans: c
Q 53) Let f : R R be defined as f(x) = x5
a) f is one-one onto
b) f is many-one onto
c) f is one-one but not onto
d) f is neither one-one nor onto 
Ans: a

Q 54) The function f : N →  N defined by f(x) = x2 + x + 1 is
a) one-one onto
b) one-one but not onto
c) onto but not one-one
d) neither one-one nor onto 
Ans: b

Q 55) Let f : R → R be defined by f(x) =   , then f is
a) one-one
b) not one-one
c) identity function
d) zero function
Ans: b
Solution Hint f(0) = f(26) but 0 ≠ 26 f(x) is not one-one

Q 56) Let f : R → R be defined by f(x) = x4, then
a) f is one-one onto
b) f is many-one onto
c) f is one-one but not onto
d) f is neither one-one nor onto 
Ans: d

Q 57) Let f : R → R be defined by f(x) = 3x , then
a) f is one-one onto
b) f is many-one onto
c) f is one-one but not onto
d) f is neither one-one nor onto 
Ans: a

Q 58) Let f : R → R be defined by f(x) =   , then f is
a) one-one
b) onto
c) bijective
c) f is not defined
Ans: d
Solution Hint
Since at x = 0, f(x) is not defined So f(x) is not defined for all x ∈  R

Q 59) The number of all one-one functions from the set {1, 2, 3, 4, ……………., n} to itself =
a) n
b) n!
c) n2

d) nn 

Ans: b

Q 60) Let f : R → R be defined by f(x) = |x|, then
a) f is one-one onto
b) f is many-one onto
c) f is one-one but not onto
d) f is neither one-one nor onto 
Ans: d

Q 61) If the set A contains 5 elements and the set B contains 6 elements, then the number of one-one and onto mappings from A to B is
a) 720
b) 120
c) 0
d) none of these
Ans: c
Solution Hint
n(A) < n(B) Every element of set A can have unique image so f is one-one
If f(x) is one-one and n(B) > n(A) then one element in set B do not have their pre-image in set A. 
Due to this range of f(x) ≠  co-domain 
⇒ f(x) is not onto function.
So there is no mapping from A to B for which f(x) is one-one and onto.





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