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Mr530
Oct31-09, 04:51 PM
http://img257.imageshack.us/img257/7161/physics.png

I only have one more chance at this problem and I can't understand why it isn't 1. I assumed that power in = power out and power = current x voltage. If the voltage remains constant, wouldn't the current as well?

"In the circuit shown, how many volts are impressed across and how many amps flow through the lightbulb?"

(120V ac)--> 100 turns -->10 turns [1 A] --> 10 turns --> 100 turns --> lightbulb

rl.bhat
Oct31-09, 07:33 PM
Input power = [120V]*[I A]
Out put power = [..V]*[..A] ?

Mr530
Nov1-09, 08:50 AM
i'm still confused... are you saying 120v * 1 amp? Sorry, I am really bad at electricity, but dont the turns mean anything?

rl.bhat
Nov1-09, 08:57 AM
120v * 1 amp
It is not one, it is 'I'
In the first transformer, what is the out put power? From that find the input current.

Mr530
Nov1-09, 04:16 PM
so if I use V=IR how would I calculate I? I= V/R. but what do I plug in as the resistance? I am so bad at physics :(

rl.bhat
Nov1-09, 06:35 PM
From the tern ratio you can find the output voltage in the first transformer. The current is given. Find the output power. Equate it to input power and find the input current.

Mr530
Nov1-09, 07:33 PM
I am still confused. "The current is given?" maybe I am just fundamentally misinterpreting the diagram. Does it say "1A" or "IA." and either way, what does it mean?

Mr530
Nov1-09, 09:00 PM
I figured it out! Thank you so much!