The primary coil of an ideal transformer has 100 turns and its secondary coil has 400 turns. If the ac current in the secondary coil is 2 A, what is the current in its primary coil?
A) 1/4 A
B) 8 A
C) 4 A
D) 2 A
E) 1/2 A

Question

Quizplus · Accepted Answer

The current in the primary coil can be found using the transformer equation $I_1/I_2 = N_2/N_1$, where $I_1$ and $I_2$ are the currents in the primary and secondary coils, respectively, and $N_1$ and $N_2$ are the number of turns in the primary and secondary coils, respectively. Given $N_1 = 100$, $N_2 = 400$, and $I_2 = 2A$, solving for $I_1$ gives $I_1 = (N_2/N_1) \times I_2 = (400/100) \times 2 = 4 \times 2 = 8A$.

The Primary Coil of an Ideal Transformer Has 100 Turns