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

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

A). 10

B). '55'

C). '10'

D). Error

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

A). String

B). Object

C). Undefined

D). Number

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

A). Number

B). String

C). Object

D). Undefined

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

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

A). null

B). undefined

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 symbol is used to represent a boolean value in JavaScript?

A). #

B). $

C). !

D). true/false

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 true == 1 in JavaScript?

A). true

B). false

C). Error

D). 1

Which of the following is a primitive data type in JavaScript?

A). Array

B). Object

C). Function

D). String