Which symbol is used to represent a boolean value in JavaScript?

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

A). String

B). Object

C). Undefined

D). Number

What is the default value of a variable in JavaScript if it is not initialized?

A). null

B). undefined

C). 0

D). 'undefined'

Which of the following is a valid JavaScript symbol?

A). symbol

B). &symbol

C). #symbol

D). Symbol('description')

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

A). 10

B). '55'

C). '10'

D). Error

What is the result of the expression true == 1 in JavaScript?

A). true

B). false

C). Error

D). 1

What happens when you add two numbers using the + operator in JavaScript?

A). The numbers are concatenated

B). The numbers are multiplied

C). The numbers are added

D). An error occurs

What is the result of the expression true + false in JavaScript?

A). true

B). false

C). 1

D). 0

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 primitive data type in JavaScript?

A). Array

B). Object

C). Function

D). String