Question

An ideal transformer has $50$ turns in its primary winding and $25$ turns in its secondary winding. If the current in the secondary winding is $4\text{A}$, what will be the current in the primary winding, when a $200\text{V}$ alternating voltage is applied across the primary?

• A. $3\text{A}$
• B. $1\text{A}$
• C. $2\text{A}$
• D. $4\text{A}$

Answer 1

The correct option is C $2\text{A}$

Using the ideal transformer equation, we have,

$\frac{E_S}{E_P}=\frac{N_S}{N_P}=\frac{i_P}{i_S}$

$\Rightarrow E_S=\frac{N_S}{N_P}\times E_P$

$\Rightarrow E_S=\frac{25}{50}\times 200=100\text{V}$

Also,

$E_S{i}_S=E_P{i}_P$

$\therefore i_P=\frac{E_S{i}_S}{E_P}=\frac{100\times 4}{200}=2\text{A}$

Hence, option $\left(C\right)$ is the correct answer.