Physics● Common
Ohm's law
Ohms lag
Discovered 1827 · Georg OhmEUREKA 05
Ohm's law●
The ideaThe current through a resistor grows in step with the voltage across it.
U = R · I
Lets you predictThe current before you switch on.
Tests usually ask
- Find current, voltage or resistance
- Resistors in series
Scan for the full explanation and a practice question.
Eureka · 05/10
Eureka · 05/10
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Physics ● Common: a core idea every course needs
Ohm's law
Swedish: Ohms lag · Discovered: Georg Ohm, 1827
The current through a resistor grows in step with the voltage across it.
U = R · I
Why it works
Voltage is the push, current is the flow, resistance is how narrow the pipe is. Double the push and you double the flow.
Resistors in series simply add up: 10 Ω and 20 Ω in a row act like one 30 Ω resistor.
What it lets you predict
The current before you switch on.
How tests ask about it
- Find current, voltage or resistance
- Resistors in series
Try it
A 9 V battery is connected to a 30 Ω resistor. What is the current?
Show the answer
I = U / R = 9 / 30 = 0.3 A.
Connects to
Wins these Lab Duel challenges
- Not in the first challenge set yet.