Atransformer connected to a 120--v ac line is to supply 12.0v (rms) to a portable electronic device. the load resistance in the secondary is 4.70 ohms
1) what should the ratio of primary to secondary turns of the transformer be?
2) what rms current must the secondary supply?
i = a
3) what average power is delivered to the load?
p = w
4) what resistance connected directly across the source line (which has a voltage of 120? v ) would draw the same power as the transformer?
r = ohms
We don't know anything about the structure or materials of the real transformer, so all we can do is assume that it's ideal, with no losses.
1). N1/N2 = 120v/12v = 10:1
2). I = V/R = 12/4.7 = 2.55 Amperes
3). Power = V²/R = (12)² / 4.7 = 30.64 watts
4). Power = V² / R
R = V² / power
R = (120)² / (30.64 watts)
R = 470 ohms
c, 1a hope this