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Variables and Data Types
Question 1
What happens when we console.log() a variable?
- A
It debugs the entire code
- B
It prints the value of the variable to the console
- C
It creates a memory block in system
- D
It is used to delete the variable's block of memory
Question 2
Which keyword is used to declare a variable that cannot be reassigned?
- A
var
- B
let
- C
const
- D
static
Question 3
Which of the following variable names are correct according to JavaScript?
- A
1name;
- B
#name;
- C
_name;
- D
@name;
Question 4
What will be the output of the following code?
let x = "Hello";
let y = 5;
console.log(x + y);
- A
Hello5 - B
5Hello - C
NaN - D
Hello
Question 5
What is the difference between var, let, and const?
- A
var is block-scoped, let and const are function-scoped.
- B
var is function-scoped, let and const are block-scoped.
- C
var and let are block-scoped, const is function-scoped.
- D
All are block-scoped.
Question 6
Which of the following is a primitive data type in JavaScript?
- A
Array
- B
Object
- C
Symbol
- D
Function
Question 7
What is the output of the following code?
let x;
console.log(typeof x);
- A
null
- B
undefined
- C
object
- D
string
Question 8
Which of the following is a valid way to interpolate a variable into a string?
- A
"My age is " + age;
- B
`My age is ${age}`;
- C
"My age is ${age}";
- D
Both a and b
Question 9
How do you check the type of a variable in JavaScript?
- A
Using typeof
- B
Using instanceof
- C
Using Object.prototype.toString.call()
- D
All of the above
Question 10
What is the output of the following code?
console.log(5 + 5 + "5");
- A
"105"
- B
15
- C
NaN
- D
"55"
There are 10 questions to complete.
