With ideal connecting wires and a fixed resistance, the closed-circuit current is voltage divided by resistance. Increasing the resistance reduces the current for the same battery voltage. The open circuit has no complete path in this simplified direct-current model. A real filament bulb's resistance changes with temperature, so its brightness is not calculated as a faithful lamp simulation.
Light, sound and electricity · Discover & try
What does a bulb need to light?
Reading level 4 of 5 · FluentChange
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circuit
A connected route for electric current.
voltage
A potential difference that can drive current.
Watch · Try · Explain
See how it works
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Virtual low-voltage DC loop with a fixed resistive load; never a wiring instruction for mains electricity.
What to look for
- The return path matters
- An open switch stops steady current
- Charge continues through the load
Explain what you noticed
Both wires touch a bulb, but one ends before reaching the second battery terminal. What is needed?
Keep this idea: A conducting route must connect through the load and back to the battery.
Follow the sources
Source material checked 2026-10-28. Explanations and activities by Nepedia. Source links do not imply endorsement.
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