In a laboratory demo, a 12 v car battery powers two 12 v, 24 w lamps in parallel.
the current is measured using an ammeter (of resistance 10 ohms) which is connected in series with each of the bulbs in turn. what will the ammeter read? comment on your answer.
i got two answers, not sure which is right (if any)
1) 1.2 a because i = v/r, therefore 12/10 = 1.2 a
2) 0.75 a because:
i = p/v, therefore current of bulbs normally is 2a.
r = v/i, therefore r = 12/2 = 6 ohms
total resistance = 6+10 = 16 ohms
i = v/r, therefore 12v/16ohms = 0.75 a