Nothing Uses Up the Current

You'll learnwhy two ammeters in one loop always agree, what a bulb actually spends, and why the current changes the moment the circuit does.

Two identical bulbs share one series loop, and the second one glows just as brightly as the first. So what is the first bulb using up? Twelve short steps; press Next for each one.

12 STEPS · 6 QUICK CHECKS · CHARGE IS CONSERVED · ENERGY IS SPENT · v2

both meters agree · bulbs spend volts per coulomb, never amperes

Before you start

What you're looking at

A series loop with a battery, two identical bulbs and two ammeters. The dots are the mobile charges already sitting inside the wire.

The question

If the first bulb is clearly doing something, what exactly is it using up?

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