Physics · Chapter 07

⚡ Electricity Basics

Current, voltage, circuits.

💡 Ohm's Law

Voltage (V) is the electrical "push" — measured in volts. Current (I) is the flow of electrons — measured in amperes. Resistance (R) opposes the flow — measured in ohms (Ω).

V = I × R

More voltage → more current. More resistance → less current. A circuit needs a complete loop — break it anywhere and the flow stops (this is what a switch does).

Simple electric circuit — battery, bulb, switch, connecting wires
Simple electric circuit — battery, bulb, switch, connecting wiresWikimedia Commons / CC BY-SA 3.0
High-voltage power transmission lines — step-up transformers reduce current loss
High-voltage power transmission lines — step-up transformers reduce current lossWikimedia Commons / CC BY-SA 3.0
🎬

The Glowing Circuit

Animation
+ − Battery Resistor (R) CURRENT (I = V/R) 0.5 A V = 6 V · R = 12 Ω

Electrons flow from − to +. More voltage = brighter bulb. More resistance = dimmer.

🧪

Build Your Circuit

Experiment

Change voltage and resistance. Watch the bulb glow brighter or dimmer.

6 V
12 Ω
Current (V ÷ R)0.50 A
Power (V × I)3.0 W
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