## Topics/Questions discussed in this video:

**Question 1.** Let R be the relation in the set N given by R = {(a, b) : a = b – 2, b \in 6}. Choose the correct answer. A. (2, 4) ∈ R B. (3, 8) ∈ R C. (6, 8) ∈ R D. (8, 7) ∈ R **(N)**

**Question 2.** Let A= {1, 2, 3,} and define R = {(a, b): a – b = 12}. Show that R is empty relation on Set A. **(B)**

**Question 3.** Let A be the set of all students of a boy’s school. Show that the relation R in A given by R = {(*a*, *b*) : *a* is sister of *b*} is the empty relation and R′ = {(*a*, *b*) : the difference between heights of *a* and *b* is less than 3 meters} is the universal relation. **(N)**

**Question 4.** If A is the set of students of a school then write, which of following relations are Universal, Empty or neither of the two. R_{1} = {(*a*, *b*) : *a*, *b* are ages of students and |*a* – *b*| = 0} R_{2} = {(*a*, *b*) : *a*, *b* are weights of students, and |*a* – *b*| = 0} R_{3} = {(*a*, *b*) : *a*, *b* are students studying in same class} **(B)**

**Question 5.** Let A = {1, 2, 3,} and define R = {(a, b): a + b = 0}. Show that R is a universal relation on set A. **(B)**