#AP Physics C: E&M - Power in Circuits: The Ultimate Study Guide ⚡

Hey future physicists! Let's dive into the world of power in circuits. This guide is designed to be your go-to resource, especially the night before the exam. We'll break down the concepts, highlight the key points, and get you feeling confident and ready to ace that test!

#Electrical Power: The Basics

#What is Power? 🤔

In simple terms, power is the rate at which energy is transferred or converted. In electrical circuits, power tells us how quickly electrical energy is being transformed into other forms of energy, like heat or light. Remember this fundamental concept:

#Power Equations: Your Toolkit 🧰

The fundamental equation for power is:

$$P = \frac{dW}{dt}$$

Where:

• P is power (in Watts)
• dW is the change in energy (in Joules)
• dt is the change in time (in seconds)

In electrical terms, we can express power using voltage (V) and current (I):

$$P = IV$$

Using Ohm's Law ($V = IR$), we can derive two more useful equations:

By substituting Ohm's Law ($V=IR$) into $P=IV$, we get:

$$P = I^2R$$

Or, by substituting $I=V/R$ into $P=IV$, we get:

$$P = \frac{V^2}{R}$$