Current in a series circuit
A 12 V battery is connected to a 2 Ω resistor and a 4 Ω resistor in series. What current flows?
Answer A: explanation for every choice
A
Correct. Series resistances add to 6 Ω, so I = V/R = 12/6 = 2 A.
B
This uses only the 4 Ω resistor.
C
This uses only the 2 Ω resistor.
D
This uses the parallel equivalent resistance, about 1.33 Ω.
TakeawaySeries resistances add, and the current is the same through each.
Equations usedOhm's lawResistors in series and parallel
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