Why is the voltage across a bulb the same as the battery in a series circuit?
2 Answers
The resistance of connecting wire is negligible.
Explanation:
There is no drop of voltage in the line So bulb gets the same voltage as the battery.
I disagree with your statement in the question.
Explanation:
The voltage across a bulb is the same as the battery voltage in a series circuit ONLY IF the bulb and the battery are the only components in the circuit. If there are any other loads in series with the bulb, the voltage across a bulb is NOT the same as the battery voltage in a series circuit.
Did you mean to ask, "Why is the voltage across a bulb the same as the battery in a PARALLEL circuit?" For that question, I could explain.
If you draw a parallel circuit with a bulb in one of the parallel branches, a radio in another branch, and an iphone recharging in a third branch, then the bulb, radio, and iphone would all have the battery's voltage across them. And the reason can be seen from your sketch. From the 2 terminals of the bulb, you can follow the wires directly back to the battery without going thru any of the other devices.
I hope this helps,
Steve
