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.