A step-up transformer operates on a 220 V line and supplies a current of 2 A. The ratio of primary and secondary winding is 1 : 25. Assuming 100% efficiency, the output power of the transformer is:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 11000 W
In a transformer the voltages are in the ratio of the turns, and the current the transformer supplies is the current in the secondary (load) circuit.
\( \displaystyle V_s = V_p\,\frac{N_s}{N_p} = 220 \times 25 = 5500\,\mathrm{V} \)
\( \displaystyle P_{\mathrm{out}} = V_s I_s = 5500\,\mathrm{V} \times 2\,\mathrm{A} = 11000\,\mathrm{W} \)
With 100% efficiency the input power is the same, 11000 W, drawn as \( 50\,\mathrm{A} \) from the 220 V line.