Resistance and circuits

Question

The resistance of each brake lightbulb on an automobile is 8.5 Ω.

 Use the fact that cars have 12-V electrical systems to compute the current that flows in each bulb if they are connected in series. (For simplicity, assume that the circuit is only composed of one brake lightbulb and the car battery.)

Answer 1

I am assuming you mean that the circuit consists of the battery and the two bulbs in series.

First, find the total resistance by adding the resistances of the two bulbs. R total = 8.5 + 8.5 = 17 ohms.

Use Ohms law to calculate the current through each bulb. I = E/R = 12 V / 17 Ω = 0.71 amps.