A transformer has 200 and 500 turns in its primary and secondary coils, respectively. If the primary coil is connected to an a.c. source and it draws a rms current of 5 A, what is the rms current in its secondary coil?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 2.0 A
For an ideal transformer the power in the two coils is equal, so the currents are in the inverse ratio of the numbers of turns.
\( \displaystyle \frac{I_s}{I_p} = \frac{N_p}{N_s} \)
\( \displaystyle I_s = 5 \times \frac{200}{500} \)
\( \displaystyle I_s = 2.0\,\mathrm{A} \)