1. The problem statement, all variables and given/known data A total charge of 50 Ah is stored in a 12 V battery of a car. Each of the bulbs of the four parking lights is labelled 3,6 W / 12 V. 2. Relevant equations a) Find the current from the battery when only the parking lights are switched on. b) What is the resistance of one bulb? c) How long does it take before the battery becomes dead if the parking lights are on? Assume that the internal resistance of the battery and the resistances of the connecting wires are negligible. 3. The attempt at a solution First of all. The given data does not clarify what type of circuit that the bulbs are wired, so I assume that they are wired in parallel. (sorry I don't know how to use Tex codes. I just tried some but some work, some don't. So I'm not going to use texcode). P=VI and I = V/R ======> P= V2/R =====> R = V2/P = 122/ 3,6 =40 (Ω) Four bulbs are connected in parallel, so: 1/Rtotal = 1/R1+1/R2+1/R3+1/R4=4/R=4/40=10 (Ω) the current from the battery when only the parking lights are switched on: I = V/Rtotal = 12/10=1.2 (A) Time it takes before the battery becomes dead: t = 50/1.2 = 41.666666....~41.2 hours. I wonder if my solution is correct ?