haquer
Answered

Looking for answers? Westonci.ca is your go-to Q&A platform, offering quick, trustworthy responses from a community of experts. Join our Q&A platform to get precise answers from experts in diverse fields and enhance your understanding. Discover detailed answers to your questions from a wide network of experts on our comprehensive Q&A platform.

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

Sagot :

AL2006
Your second solution is excellent, and well done. Ammeters are usually assumed to have zero resistance, and that would be your first solution. Your second one shows how much difference it can make when the meter itself has substAntial resistance. / / / Notice also that the poor meter has to dissipate a little more than 5 watts. That's a lot.
We appreciate your visit. Our platform is always here to offer accurate and reliable answers. Return anytime. We hope you found this helpful. Feel free to come back anytime for more accurate answers and updated information. Get the answers you need at Westonci.ca. Stay informed with our latest expert advice.