21 questions · from 3 interviews
Physics Wallah interview questions
Every question candidates reported from their Physics Wallah interviews, most frequently asked first. Each links to the write-up it came from, so you can see the round and how it went.
Physics Wallah coding and DSA questions
- 01
Longest Increasing Subsequence
Given an integer array, find the length of the longest strictly increasing subsequence.
Medium · From Physics Wallah - Staff Backend Engineer - Sept 2026
Physics Wallah system design questions
- 01
Design an Experimentation/Feature Flag System
Design a system that provides feature flag/experimentation capabilities. The system must handle 2 million requests per minute to check variant assignment. It should be callable from internal services, preferably via a client library, use consistent hashing to…
- 02
Design an E‑book Store Service
Design a service for an e‑book store that can handle 6 million concurrent reads for a book at launch. Users can add books to a library and purchase them. Users should only be able to view preview pages of books and cannot download full content unless the book…
- 03
Design a Notification System
The interviewer presented a scenario and asked me to design a notification system. This involved detailing the database schema and outlining the necessary APIs for its functionality.
Physics Wallah other questions
- 01
JavaScript Datatypes
Discuss different datatypes in JavaScript.
From Physics Wallah Interview Experience for SDE 1 (Frontend)
- 02
Var, Let, and Const Differences
Explain the difference between var, let, and const.
From Physics Wallah Interview Experience for SDE 1 (Frontend)
- 03
Hoisting in JavaScript
Explain hoisting and provide an implementation example using var, let, and const.
From Physics Wallah Interview Experience for SDE 1 (Frontend)
- 04
Temporal Dead Zone
Describe the Temporal Dead Zone in JavaScript.
From Physics Wallah Interview Experience for SDE 1 (Frontend)
- 05
Normal vs. Arrow Functions
Explain the differences between normal and arrow functions, covering syntax and 'this' behavior.
From Physics Wallah Interview Experience for SDE 1 (Frontend)
- 06
Callback Functions
Explain what callback functions are.
From Physics Wallah Interview Experience for SDE 1 (Frontend)
- 07
Debouncing and Throttling
Explain debouncing and throttling.
From Physics Wallah Interview Experience for SDE 1 (Frontend)
- 08
Map, Reduce, and Filter Differences
Explain the difference between map, reduce, and filter array methods in JavaScript.
From Physics Wallah Interview Experience for SDE 1 (Frontend)
- 09
Props vs. State in React
Explain the difference between props and state in React.
From Physics Wallah Interview Experience for SDE 1 (Frontend)
- 10
React Hooks Usage
Discuss the usage of React hooks.
From Physics Wallah Interview Experience for SDE 1 (Frontend)
- 11
React Lifecycle Methods and Hooks
Explain React lifecycle methods and how they map to hooks.
From Physics Wallah Interview Experience for SDE 1 (Frontend)
- 12
React Fragments
Explain what React Fragments are.
From Physics Wallah Interview Experience for SDE 1 (Frontend)
- 13
Cleanup Function in useEffect
Explain the cleanup function within the useEffect hook.
From Physics Wallah Interview Experience for SDE 1 (Frontend)
- 14
Counter with Custom Hook
Implement a counter using useState and extend it with a custom hook to store the previous value.
From Physics Wallah Interview Experience for SDE 1 (Frontend)
- 15
Controlled vs. Uncontrolled Components
Explain the difference between controlled and uncontrolled components in React.
From Physics Wallah Interview Experience for SDE 1 (Frontend)
- 16
CSS Box Model
Explain the CSS box model.
From Physics Wallah Interview Experience for SDE 1 (Frontend)
- 17
Centering a Div with CSS
Describe different ways to center a div using CSS.
From Physics Wallah Interview Experience for SDE 1 (Frontend)
Physics Wallah interview questions FAQ
What questions are asked in Physics Wallah interviews?
Candidates reported 21 distinct questions across 3 Physics Wallah interviews. 1 coding and DSA questions, 3 system design questions, 17 other questions.