Which of the following is null set?
Which of the following is a null set?
- A.
{0}
- B.
{ }
- C.
{1, 2, 3}
- D.
{x | x > 5}
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Correct answer: B
Definition: A null set is a set with no elements.
Identify which expressions are empty or non-empty:
{ } denotes the empty set (also written as ∅). It contains no elements, so this is the null (empty) set and is the correct answer.
{0} is a set that contains the single element 0. Because it has an element, it is not empty.
{1, 2, 3} contains the elements 1, 2, and 3, so it is not empty.
{x | x > 5} describes all numbers greater than 5; it includes many elements, so it is not empty.