Answer:
(a) 0.075
(b)20.1 mA
(c) 2.412 W
Explanation:
Vs = 9 V, is = 268 mA = 0.268 A
Vp = 120 V
(a) Let the number of turns in primary coil is Np and the number of turns in secondary coil of the transformer is Ns.
Ns / np = Vs / Vp
Ns / Np = 9 / 120
Ns / Np = 3 : 40 = 0.075
(b) Let the current drawn from the wall socket is ip.
Ns/ Np = ip / is
0.075 = ip / 0.268
ip = 0.0201 A = 20.1 mA
(c) Power delivered by the socket = Vp x ip = 120 x 0.0201 = 2.412 W
Power sent to the batteries = Vs x is = 9 x 0.268 = 2.412 W