What is the keyword used to declare variables in JavaScript?

Which of the following is NOT a valid variable name in JavaScript?

A). _myVariable

B). 2ndVariable

C). $myVariable

D). my-Variable

What will be the value of x after the following code executes: let x = 10; x += 5;?

A). 15

B). 5

C). 10

D). undefined

Which method is used to convert a string to a number in JavaScript?

A). toString()

B). parseInt()

C). parseFloat()

D). toNumber()

What will be the output of the following code: console.log('Hello ' + 'World');?

A). Hello World

B). Hello + World

C). Hello +World

D). HelloWorld

Which data type is used to represent whole numbers in JavaScript?

A). number

B). integer

C). float

D). string

What will be the output of the following code: console.log(typeof 'Hello');?

A). string

B). number

C). undefined

D). boolean

What is the purpose of the NaN (Not a Number) value in JavaScript?

A). To represent a number that is not a valid JavaScript number

B). To represent a zero value

C). To represent an infinite value

D). To represent an empty string

What is the purpose of using the === operator in JavaScript?

A). Strict equality comparison

B). Loose equality comparison

C). Assignment operator

D). Addition operator

What is the scope of a variable declared using the let keyword in JavaScript?

A). Block scope

B). Function scope

C). Global scope

D). Local scope

What will be the output of the following code: console.log(parseInt('10.5'));?

A). 10

B). 5

C). '10.5'

D). NaN (Not a Number)