Which data type is used to represent whole numbers 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

Which symbol is used for string concatenation in JavaScript?

A). +

B). -

C). *

D). /

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

A). Hello World

B). Hello + World

C). Hello +World

D). HelloWorld

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 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;

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

A). string

B). number

C). undefined

D). boolean

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

A). _myVariable

B). 2ndVariable

C). $myVariable

D). my-Variable

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 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 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