Question

A power transmission line feeds input power t 2300 V to a step-down transformer with its primary windings having 4000 turns. The output power is delivered at 230 V by the transformer. If the current in the primary of the transformer is 5A and its efficiency is 90%, the output current would be :

• A. 25 A
• B. 50 A
• C. 35 A
• D. 45 A

Answer 1

The correct option is D 45 A

$\eta =\frac{P_{out}}{P_{in}}=\frac{V_s{I}_s}{V_p{I}_p}$
$\Rightarrow 0.9=\frac{23\times I_s}{230\times 5}$
$\Rightarrow I_s=45A$