🔹 MCQs Of Class 1
React Basics
b) CSS Framework
c) JavaScript Library ✔️
d) Database
2. Who developed React?
a) Google
b) Microsoft
c) Twitter
d) Facebook ✔️
3. What type of applications is React best suited for?
a) Operating Systems
b) Desktop Applications
c) Single Page Applications ✔️
d) Games
4. What is the main feature of React?
a) Server-side rendering
b) File Management
c) Component-Based UI ✔️
d) Browser Extension
5. Which of the following is NOT a feature of React?
a) Virtual DOM
b) One-way data binding
c) Template-based syntax
d) Component reusability ✔️
6. React is mainly used for:
a) Back-end Development
b) Designing Databases
c) Building User Interfaces ✔️
d) Mobile Apps Only
7. React is a library for which language?
a) PHP
b) Java
c) JavaScript ✔️
d) Python
8. What kind of architecture does React follow?
a) MVC
b) MVVM
c) Component-Based ✔️
d) Client-Server
9. Which of the following best describes React?
a) Full-stack framework
b) JavaScript library for UI ✔️
c) Server-side rendering tool
d) Backend runtime
10. Which React feature allows for UI reusability?
a) APIs
b) Hooks
c) Components ✔️
d) Services
🔹 Section 2: SPA vs MPA
11. SPA stands for:
a) Styled Page App
b) Single Page Application ✔️
c) Static Page Application
d) Service Page Application
12. MPA stands for:
a) Master Page App
b) Multi Page Application ✔️
c) Main Page Application
d) Modular Page App
13. In SPA, how are page transitions handled?
a) With full-page reloads
b) Through AJAX
c) Dynamically without reload ✔️
d) With cookies
14. Which of the following is an example of an SPA?
a) Amazon
b) Facebook ✔️
c) Yahoo
d) Wikipedia
15. In MPA, what happens when navigating between pages?
a) No reload occurs
b) Only partial content reloads
c) Full page reload occurs ✔️
d) Content changes with JavaScript only
🔹 Section 3: Virtual DOM
16. What is Virtual DOM in React?
a) Real DOM
b) An exact copy of the browser DOM
c) Lightweight representation of real DOM ✔️
d) Database of DOM elements
17. Why is Virtual DOM used in React?
a) For styling pages
b) For storing component data
c) To increase rendering speed ✔️
d) For debugging only
18. What happens when state changes in React?
a) Real DOM is modified directly
b) Page reloads
c) Virtual DOM updates ✔️
d) No changes occur
19. How does React update the DOM efficiently?
a) It recreates the DOM
b) It performs manual editing
c) It compares new and old Virtual DOM ✔️
d) It clears the whole DOM
20. React compares the new Virtual DOM with the previous one using:
a) AJAX
b) Diffing Algorithm ✔️
c) Compiler
d) Server Scripts
🔹 Section 4: JSX Basics
21. What is JSX?
a) Java Syntax Extension
b) JavaScript XML ✔️
c) JavaScript eXecution
d) XML Script
22. What is the purpose of JSX in React?
a) Write CSS
b) Write HTML in JavaScript ✔️
c) Create database queries
d) Send HTTP requests
23. JSX must return how many parent elements?
a) One ✔️
b) Two
c) Many
d) None
24. Which of the following is valid JSX?
a) <div>Hello World</div> ✔️
b) <div>Hello World
c) div>Hello World</div>
d) print(“Hello”)
25. What is used in JSX instead of class?
a) classname
b) class-name
c) className ✔️
d) cssClass
26. Which of these can be embedded inside JSX using curly braces {}?
a) HTML
b) CSS
c) JavaScript expressions ✔️
d) SQL
27. What will be the result of {2 + 2} in JSX?
a) 2+2
b) 4 ✔️
c) "2 + 2"
d) Error
28. What is NOT allowed in JSX?
a) Using HTML tags
b) Using JavaScript expressions
c) Using unclosed tags ✔️
d) Nesting components
29. Which syntax is correct in JSX?
a) <br>
b) <br /> ✔️
c) <br/ >
d) br;
30. JSX is converted into:
a) HTML
b) XML
c) JavaScript ✔️
d) TypeScript
🔹 Section 5: Environment Setup
31. Which tool is used to create a new React project?
a) npm init
b) create-react-app ✔️
c) webpack
d) nodemon
32. What command is used to create a new React app?
a) npm create react-app
b) npx create-react-app ✔️
c) nvm install react
d) react-init
33. React apps are started using:
a) npm launch
b) npm open
c) npm start ✔️
d) npm begin
34. What file is the entry point of a React app?
a) App.js
b) main.js
c) index.js ✔️
d) start.js
35. Which file contains the root HTML in React?
a) index.js
b) index.html ✔️
c) App.js
d) main.html
36. Which folder contains the HTML file in React project?
a) src
b) public ✔️
c) components
d) assets
37. Which folder contains the React components?
a) html
b) public
c) src ✔️
d) lib
38. Which dependency is required to run a React app?
a) Python
b) React DOM ✔️
c) Apache
d) Bootstrap
39. Which code editor is commonly used for React development?
a) NetBeans
b) Eclipse
c) VS Code ✔️
d) Turbo C++
40. To install React globally, you need:
a) Node.js ✔️
b) MySQL
c) Git
d) Java
🔹 Section 6: Conceptual Understanding
41. React updates only the changed parts of the DOM using:
a) Real DOM
b) Virtual DOM ✔️
c) Inline CSS
d) Class selectors
42. JSX looks like HTML but is actually:
a) TypeScript
b) JavaScript ✔️
c) Python
d) SQL
43. The App.js file in React contains:
a) Backend logic
b) HTML code
c) Root component ✔️
d) Styles
44. index.js is used to:
a) Define API routes
b) Launch the React component tree ✔️
c) Set up database
d) Add global styles
45. React components should start with:
a) lowercase
b) Capital letter ✔️
c) Symbol
d) Number
🔹 Section 7: Short MCQs for Practice
46. React uses which programming concept?
a) OOP
b) Functional Programming ✔️
c) Procedural Programming
d) Imperative Programming
47. Which is NOT a React tool?
a) Babel
b) Webpack
c) React Router
d) Django ✔️
48. In React, the HTML inside JS is known as:
a) JSX ✔️
b) TSX
c) HJS
d) HTS
49.To comment in JSX, we use:
a) <!-- -->
b) /* */
c) {/* */} ✔️
d) //
50. React app runs on which port by default?
a) 8000
b) 5000
c) 3000 ✔️
d) 8080
51. Which company maintains React?
a) Google
b) Facebook ✔️
c) Microsoft
d) Amazon
52. Which command starts the development server?
a) npm run dev
b) npm start ✔️
c) npx serve
d) react-run
53. JSX helps in writing:
a) Database code
b) HTML in JavaScript ✔️
c) Styling only
d) APIs
54. Which method renders a component to the DOM in React?
a) renderComponent()
b) ReactDOM.render() ✔️
c) component.show()
d) showDOM()
55. JSX expressions must be wrapped in:
a) Curly braces ✔️
b) Quotes
c) Parentheses
d) Angle brackets
56.What’s the command to navigate into a newly created React app folder?
a) cd app
b) cd react-app
c) cd my-app ✔️ (depends on project name)
d) goto app
57.React components are:
a) CSS Files
b) HTML Snippets
c) JavaScript Functions ✔️
d) SQL Queries
58.How many root elements should a JSX return?
a) One ✔️
b) Two
c) Many
d) None
59.React encourages what style of development?
a) Procedural
b) Declarative ✔️
c) Imperative
d) Command-Line
