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

What is the keyword used to declare variables in JavaScript?

A). let

B). variable

C). var

D). const

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)

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

A). Hello World

B). Hello + World

C). Hello +World

D). HelloWorld

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

Which symbol is used for string concatenation in JavaScript?

A). +

B). -

C). *

D). /

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

A). toString()

B). parseInt()

C). parseFloat()

D). toNumber()

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 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