Given,
Primary voltage V1 = 220 V
Primary turns N1 = 200 turns
Secondary turns N2 = ?
Secondary voltage V2 = 33 V
According to formula,
\(\frac{V2}{V1}=\frac{N2}{N1}\)
N2 = 200 * 33 / 220
N2 = 30
Hence, the number of turns in secondary coil must be 30 turns.