A power transmission line feeds input power at 2300 V to a stepdown transformer with its primary windings having 4000 turns.

Input voltage, V1 = 2300

Number of turns in primary coil, n1 = 4000

Output voltage, V2 = 230 V

Number of turns in secondary coil = n2

Voltage is related to the number of turns as:

$\frac{V_{1}}{V_{2}}=\frac{n_{1}}{n_{2}}$

$\frac{2300}{230}=\frac{4000}{n_{2}}$

$n_{2}=\frac{4000 \times 230}{2300}=400$

Hence, there are 400 turns in the second winding.