A power transmission line feeds input voltage of 2200 V to a step down transformer with its primary windings having 4000 turns. The number of turns in the secondary in order to get output voltage of 220 V will be:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 400
For an ideal transformer the voltages are in the same ratio as the number of turns.
\( \displaystyle \frac{V_s}{V_p} = \frac{N_s}{N_p} \)
\( \displaystyle N_s = N_p\,\frac{V_s}{V_p} = 4000\times\frac{220\,\mathrm{V}}{2200\,\mathrm{V}} = 400 \)
The secondary has fewer turns than the primary, as it must in a step-down transformer.