Question

A transformer has $100$ turns in the primary coil and carries $8A$ current. If the input power is $1kW,$ the number of turns in secondary coil to have $500V$ of output will be

• A. $100$
• B. $200$
• C. $400$
• D. $300$

Answer 1

Answer: (C)

Given that,
$N_p=100,I_p=8A$
$V_s=500V,P_i=1kW=100W$
Input power, $P_i=V_P{I}_P$
$1000=V_p\times 8$
$V_P=125V$
Again, we know that
$\frac{N_s}{N_P}=\frac{V_s}{V_p}$
$\Rightarrow \frac{N_s}{100}=\frac{500}{125}$
$N_s=\frac{500\times 100}{125}$
$=400$