A transformer has 400 turns in the primary coil and 8000 turns in the secondary coil. It is connected to a 220 V main supply. The potential difference per turn in secondary coil is
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 0.55 V
In an ideal transformer the same changing flux links every turn of both coils, so the emf per turn is the same in the primary and the secondary. The voltages are in the ratio of the turns.
\( \displaystyle \frac{V_s}{V_p} = \frac{N_s}{N_p} \;\Rightarrow\; V_s = 220 \times \frac{8000}{400} = 4400\,\mathrm{V} \)
\( \displaystyle \text{Voltage per turn} = \frac{V_s}{N_s} = \frac{4400\,\mathrm{V}}{8000} = 0.55\,\mathrm{V} \)
Shortcut: Since the voltage per turn is the same in both coils, \( 220\,\mathrm{V}/400 = 0.55\,\mathrm{V} \) directly.