Q149 / 180 · COMEDK 2018 · Physics
A current of $5 \mathrm{~A}$ is flowing at $220 \mathrm{~V}$ in the primary coil of a transformer. If the voltage produced in the secondary coil is $2200 \mathrm{~V}$ and $50 \%$ of power is lost, then the current in the secondary will be
- A$2.5 \mathrm{~A}$
- B$5 \mathrm{~A}$
- Correct answerC$0.25 \mathrm{~A}$
- D$0.5 \mathrm{~A}$
Solution
For a transformer,
$\begin{aligned} I_{P}=5 \mathrm{~A}, V_{P} &=220 \mathrm{~V} \\ V_{S}=2200 \mathrm{~V} \end{aligned}$
Since, $50 \%$ power is lost, hence power at secondary side,
$$
\begin{array}{cl}
& P_{0}=50 \% \text { of } P_{i}=\frac{50}{100} \times 1100 \\
\Rightarrow & P_{0}=550 \mathrm{~W} \\
\Rightarrow & V_{S} I_{S}=550 \\
\Rightarrow & 2200 \times I_{S}=550 \\
\Rightarrow & I_{S}=\frac{550}{2200}=\frac{1}{4}=0.25 \mathrm{~A}
\end{array}
$$
Hence, the correct answer is option: 'C'.