Introduction to React

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Question 1

What does the following line do in a React file?

JavaScript 
import React from 'react';


  • Runs the React application

  • Imports the React library to use JSX and components

  • Imports only hooks like useState and useEffect

  • Initializes the DOM for rendering

Question 2

React follows which type of architecture for building UIs?

  • Template-driven architecture

  • MVC (Model-View-Controller) architecture

  • Component-based architecture

  • Layered architecture

Question 3


Which is the correct way to pass a prop named username with value "Anil" to the Greet component?

  • <Greet username="Anil" />

  • <Greet {username="Anil"} />

  • <Greet props.username="Anil" />

  • <Greet name=username />

Question 4

Identify the output of this component:

JavaScript 
function Greeting() {
  return <h1>Hello, welcome to React!</h1>;
}


  • Displays nothing

  • Displays "Hello, World!"

  • Displays "Hello, welcome to React!"

  • Causes a compilation error

Question 5

If multiple components need the same state data, what is the recommended approach?

  • Duplicate the state in each component

  • Pass state as props from their nearest common ancestor

  • Use CSS variables to share data

  • Avoid using state entirely

Question 6

What is the default development server port when running a Vite React app?


  • 3000

  • 5000

  • 5173

  • 8080

Question 7

When using Vite to set up a React project, which command is correct?


  • vite create react-app my-app

  • npm create vite@latest my-app --template react

  • npx create-react-app my-app

  • npm install react-vite

Question 8

In React, what is the main difference between props and state?

  • Props are mutable, state is immutable

  • Props are passed from parent, state is managed within the component

  • Both are the same, just used differently

  • State can be shared across components, props cannot

Question 9

What is the purpose of the ReactDOM.render method?

  • To manage application state

  • To compile JSX into JavaScript

  • To render a React component into the DOM

  • To define the Virtual DOM

Question 10

What will be the output of this React code?

JavaScript 
import React from 'react';
import ReactDOM from 'react-dom';
function App() {
    const greeting = "Hello";
    return <h1>{greeting} World</h1>;
}
ReactDOM.render(<App />, document.getElementById('root'));

  • Hello World

  • {greeting} World

  • "Hello World"

  • Error

There are 10 questions to complete.

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