What is the result of the expression undefined + null in JavaScript?

Which of the following is a valid way to represent the value null in JavaScript?

A). undefined

B). NULL

C). null

D). None of the above

What is a primitive value in JavaScript?

A). A complex data structure

B). A basic data type

C). A function

D). An array

What is the result of the expression 5 + '5' in JavaScript?

A). 10

B). '55'

C). '10'

D). Error

Which primitive value represents absence of value or no value assigned?

A). undefined

B). null

C). 0

D). 'undefined'

What does the Symbol data type represent in JavaScript?

A). A unique identifier

B). A number

C). A boolean value

D). An object

Which of the following statements about primitive values in JavaScript is true?

A). They are mutable

B). They are passed by reference

C). They are stored on the heap

D). They are immutable

Which of the following statements is true about JavaScript's null value?

A). It represents an empty string

B). It represents a non-existent value

C). It represents a boolean value

D). It represents a number

What happens when you try to access a variable that has not been declared in JavaScript?

A). SyntaxError is thrown

B). ReferenceError is thrown

C). TypeError is thrown

D). Undefined

Which of the following is a valid JavaScript symbol?

A). symbol

B). &symbol

C). #symbol

D). Symbol('description')

What is the data type of the value undefined in JavaScript?

A). String

B). Object

C). Undefined

D). Number