Q
How is the Undefined data type different from the Null data type in JavaScript?

Answer & Solution

Answer: Option A
Solution:
The Undefined data type represents variables that have been declared but not assigned a value, while Null represents an intentional absence of value or an explicitly cleared/reset value.
Related Questions on Average

Which data type represents variables that have been explicitly set to have no value?

A). Number

B). Undefined

C). String

D). Null

Which primitive data type represents variables that are declared but not initialized?

A). Number

B). String

C). Undefined

D). Null

Which of the following statements accurately describes the Boolean data type in JavaScript?

A). It represents textual data

B). It represents numeric data

C). It represents logical values

D). It represents an absence of value

Which primitive data type in JavaScript represents integers and floating-point numbers?

A). Number

B). String

C). Boolean

D). Undefined

Which data type is represented by the value null in JavaScript?

A). Numeric data

B). Textual data

C). Absence of value

D). Logical value

What does the expression typeof '123' return in JavaScript?

A). number

B). string

C). undefined

D). boolean

What does the expression typeof 42 return in JavaScript?

A). number

B). string

C). undefined

D). boolean

How is the Symbol data type different from other primitive data types in JavaScript?

A). Symbols can be used as object keys

B). Symbols can be compared directly

C). Symbols can be used in mathematical operations

D). Symbols can be concatenated with strings

What does the Boolean data type represent in JavaScript?

A). Textual data

B). Numeric data

C). Logical values

D). Absence of value

Which primitive data type represents unique identifiers introduced in ECMAScript 6?

A). Number

B). Symbol

C). Boolean

D). Undefined