JSON Quiz - Multiple Choice Questions (MCQ)

JSON (JavaScript Object Notation) is a widely used data interchange format known for its simplicity and ease of use. It is often used to transmit data between a server and a web application as an alternative to XML. 

Let's put your JSON knowledge to the test with this JSON Quiz! Each question is multiple-choice, and after each question, you'll find the correct answer along with a detailed explanation. Let's dive in and see how well you know your JSON!

1. What does JSON stand for?

a) JavaScript Oriented Notation 

b) JavaScript Object Notation 

c) Java Ordered Notation 

d) Java Object Notation 

Answer: 

b) JavaScript Object Notation 

Explanation: 

JSON stands for JavaScript Object Notation. It is a lightweight data-interchange format that is easy for humans to read and write and easy for machines to parse and generate.

2. What is the file extension commonly used for JSON files? 

a) .xml 

b) .js 

c) .json 

d) .html 

Answer: 

c) .json 

Explanation: 

JSON files typically have the .json file extension. They contain data in a structured format that is easy to parse and manipulate.

3. How do you represent data in JSON? 

a) Key-Value pairs 

b) Metadata 

c) Binary Data 

d) Key-Object pairs 

Answer: 

a) Key-Value pairs 

Explanation: 

In JSON, data is represented as key-value pairs. This means each value is associated with a unique key.

4. Is JSON case-sensitive? 

a) Yes 

b) No 

Answer: 

a) Yes 

Explanation: 

JSON is case-sensitive, which means it treats uppercase and lowercase letters as different characters.

5. Which symbol is used to enclose JSON objects? 

a) [] 

b) () 

c) {} 

d) "" 

Answer: 

c) {} 

Explanation: 

JSON objects are enclosed in curly braces {}. 

6. In JSON, keys must always be of which data type? 

a) String 

b) Number 

c) Boolean 

d) Object 

Answer: 

a) String 

Explanation: 

In JSON, keys must always be strings. They are enclosed in double quotes to distinguish them from values.

7. Which symbol is used to separate key-value pairs in JSON? 

a) : 

b) ; 

c) , 

d) = 

Answer: 

a) : 

Explanation: 

In JSON, key-value pairs are separated by a colon (:). The key represents the name of the property, and the value represents the data associated with that key.

8. Can you store functions in JSON? 

a) Yes 

b) No 

Answer: 

b) No 

Explanation: 

JSON is a data format. It does not support storing functions, only data.

9. What can JSON format be used for? 

a) Storing data 

b) Sending data to the server 

c) Receiving data from the server 

d) All of the above 

Answer: 

d) All of the above 

Explanation: 

JSON can be used for storing data and for data interchange between a browser and a server.

10. What does the following JSON represent?

{
   "firstName": "Ramesh",
   "lastName":"Fadatare",
   "age": 30,
   "isMarried": false
}

a) An object with four properties 

b) An array with four elements 

c) A string with JSON data 

d) A function with four arguments 

Answer: 

a) An object with four properties 

Explanation: 

The given JSON represents an object with four properties. Each property has a corresponding value.

11. How do you represent an array in JSON? 

a) [1, 2, 3] 

b) (1, 2, 3) 

c) {1, 2, 3} 

d) "1, 2, 3" 

Answer: 

a) [1, 2, 3] 

Explanation: 

Arrays in JSON are represented using square brackets ([]). The values inside the brackets are separated by commas.

12. Which of the following is true about JSON? 

a) JSON is a language 

b) JSON is a database system 

c) JSON is a data format 

d) JSON is an HTML tag 

Answer: 

c) JSON is a data format 

Explanation: 

JSON is a lightweight data interchange format.

13. How would you write a Boolean value in JSON? 

a) {'value': true} 

b) {'value': "true"} 

c) {'value': 1} 

d) {'value': 'true'} 

Answer: 

a) {'value': true} 

Explanation: 

Boolean values in JSON are written as true or false (without quotes).

14. JSON can be parsed using which of the following functions in JavaScript? 

a) JSON.parse() 

b) JSON.stringify() 

c) JSON.decode() 

d) JSON.encode() 

Answer: 

a) JSON.parse() 

Explanation: 

JSON.parse() is a function that is used to parse the JSON data in JavaScript.

15. Can JSON contain a date? 

a) Yes 

b) No 

Answer: 

b) No 

Explanation: 

JSON does not have a date data type. However, you can store dates as strings in JSON.

16. What does the "null" value represent in JSON? 

a) An empty string 

b) Zero 

c) An undefined value 

d) No value or absence of value 

Answer: 

d) No value or absence of value 

Explanation: 

In JSON, the "null" value represents the absence of a value or the intentional lack of a value.

17. How do you access the value "Ramesh" from the following JSON?

{
   "firstName": "Ramesh",
   "lastName":"Fadatare",
   "age": 30,
   "isMarried": false
}

a) json.get("firstName") 

b) json.firstName

c) json["firstName"] 

d) Both b) and c) options are correct

Answer: 

d) Both b) and c) options are correct

Explanation: 

Assuming that the JSON object is stored in a variable called json, you can access the firstName" property in two ways in JavaScript: 

Dot notation: json.firstName would return "Ramesh". 

Bracket notation: json["firstName"] would also return "Ramesh". 

18. How do you access the value "apple" from the following JSON?

{
  "fruits": ["banana", "apple", "orange"]
}

a) json.fruits[0] 

b) json.fruits[1] 

c) json.fruits.apple 

d) json.apple 

Answer: 

b) json.fruits[1] 

Explanation: 

In JSON arrays, elements are accessed using zero-based indexing. To access "apple," you use json.fruits[1].

19. What is the correct way to represent a nested object in JSON?

a)

{
  "name": "John",
  "address": {
    "city": "New York",
    "country": "USA"
  }
}

b)

{
  "name": "John",
  "address": ("city": "New York", "country": "USA")
}

c)

{
  "name": "John",
  "address": ["city", "New York", "country", "USA"]
}

d)

{
  "name": "John",
  "address": "city: New York, country: USA"
}

Answer:

a)

{
  "name": "John",
  "address": {
    "city": "New York",
    "country": "USA"
  }
}

Explanation: 

The correct way to represent a nested object in JSON is to use curly braces ({}) to define the outer object and include another object as the value of a property (address in this case).

20. What is the result of parsing the following JSON?

[
  {
    "name": "Tom",
    "age": 30
  },
  {
    "name": "Lucy",
    "age": 25
  }
]

a) An array of objects 

b) A JavaScript function 

c) A string representation of the JSON 

d) An error, JSON cannot be parsed 

Answer: 

a) An array of objects 

Explanation: 

Parsing the given JSON will result in an array containing two objects, each representing a person with name and age properties.

Conclusion

Congratulations on completing the JSON Quiz! JSON is a powerful data interchange format, and understanding its structure and manipulation methods is essential for web developers working with APIs and data transmission. 

Keep practicing and exploring JSON to become proficient in working with data effectively. Happy coding!