Question

A transformer having the efficiency of $90\%$ is working on $200V$ and $3kW$ power supply. If the current in the secondary coil is $6A$, the voltage across the secondary coil and the current in the primary coil respectively are :

• A. $300V,15A$
• B. $450V,15A$
• C. $450V,13.5A$
• D. $600V,15A$

Answer 1

Answer: (B)

$450V,15A$

Current in primary coil $=\frac{P}{V}=\frac{3000}{200}=15A$
$P_{out}=\eta$ % of $P_{in}$
$V_2{i}_2=\frac{90}{100}\times \left(3000\right)$
$\left(v_2\right)\left(6\right)=2700$
$V-2=450volt$