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

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

A). 30

B). 1020

C). 30

D). NaN

What is the initial type of a variable declared with let a;?

A). null

B). number

C). undefined

D). object

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

A). number

B). string

C). boolean

D). undefined

What does the parseInt function do in JavaScript?

A). Converts a number to a string

B). Converts a string to an integer

C). Converts a boolean to a number

D). Converts an array to a number

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

What will typeof null return in JavaScript?

A). null

B). undefined

C). object

D). number

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 the code: let y = 10; y = true;, what is the type of y after execution?

A). number

B). boolean

C). string

D). object

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

Which of the following values is considered falsy in JavaScript?

A). 1

B). 0

C). 0

D). {}