- Trending Categories
- Data Structure
- Networking
- RDBMS
- Operating System
- Java
- MS Excel
- iOS
- HTML
- CSS
- Android
- Python
- C Programming
- C++
- C#
- MongoDB
- MySQL
- Javascript
- PHP
- Physics
- Chemistry
- Biology
- Mathematics
- English
- Economics
- Psychology
- Social Studies
- Fashion Studies
- Legal Studies

- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who

# Derive An Expression For Electric Energy

Assuming electrical energy is consumed in a device, let us derive an expression for it in terms of V, I and t, where V is the potential difference applied to it, I is the current drawn by it and t is the time for which the current flows.

We know that work is done in an electrical device = W = QV where Q is an electric charge in coulombs.

Therefore, P = $\frac{W}{t}$ where P is power in watts is the rate of doing work

Now, P = $\frac{QV}{t} = I $ \times $ V where I is current in amps which is the rate of charge flow

⇒ We know V = IR from Ohms law

⇒ P = $\frac{Q}{t}IR$ = I $ \times $ V = I $ \times $ IR = $I^2R$

⇒ Energy = P $ \times $ t

⇒ **Energy = ** $I^2R$ $ \times $ t

⇒ Energy = $\frac{V}{R^2} \times $ R $ \times $ t

⇒ Energy = $\frac{V^2}{R} \times $ t

⇒ Energy = $\frac{V^2}{R} \times $ t Answer