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

What happens if you declare a variable without initializing it in JavaScript?

A). It will throw a syntax error

B). It will assign the variable a value of undefined

C). It will automatically assign a value to the variable

D). It will assign the variable a value of null

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

A). '55'

B). 10

C). 5

D). '10'

Which statement correctly assigns the value true to a boolean variable isLogged in JavaScript?

A). let isLogged = 'true';

B). let isLogged = true;

C). let isLogged = 1;

D). let isLogged = 0;

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

A). _myVariable

B). 2ndVariable

C). $myVariable

D). my-Variable

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

A). toString()

B). parseInt()

C). parseFloat()

D). toNumber()

Which variable declaration is appropriate if you want a variable to hold a constant value throughout the program execution?

A). let

B). var

C). const

D). constant

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

A). string

B). number

C). undefined

D). boolean

What is the keyword used to declare variables in JavaScript?

A). let

B). variable

C). var

D). const

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

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

A). Strict equality comparison

B). Loose equality comparison

C). Assignment operator

D). Addition operator