Which operator is used to determine the type of a variable in JavaScript?

What does the isNaN function do?

A). Checks if a value is not a number

B). Converts a value to a number

C). Checks if a value is a number

D). Converts a value to NaN

What is the result of the following code: let x = 5; x = 'hello'; console.log(typeof x);?

A). number

B). string

C). undefined

D). object

How can you check if a variable is an array in JavaScript?

A). typeof variable === 'array'

B). Array.isArray(variable)

C). variable instanceof array

D). variable.constructor === array

What does it mean that JavaScript is dynamically typed?

A). Variables do not have types

B). Variables can change type

C). Variables must be declared with a type

D). Variables cannot change type

Which of the following values is considered falsy in JavaScript?

A). 1

B). 0

C). 0

D). {}

In JavaScript, what will be the type of a variable x after x = 5 + true;?

A). number

B). string

C). boolean

D). undefined

What happens when you add a number and a string in JavaScript?

A). An error is thrown

B). The number is converted to a string

C). The string is converted to a number

D). Both are converted to boolean

What is the result of typeof [] in JavaScript?

A). array

B). object

C). list

D). undefined

Which type conversion happens automatically in the expression 3 + '5'?

A). Number to String

B). String to Number

C). Boolean to String

D). Number to Boolean

Given let a = '10'; let b = 20;, what is the result of a + b?

A). 30

B). 1020

C). 30

D). NaN