Question

Two coils $\text{P}$ and $\text{Q}$ are separated by some distance. When a current of $3\text{A}$ flows through coil $\text{P}$, a magnetic flux of ${10}^{-3}\text{Wb}$ passes through $\text{Q}$. No current is passed through $\text{Q}.$ When no current passes through $\text{P}$ and a current of $2\text{A}$ passes through $\text{Q}.$ The flux through $\text{P}$ is-

• A. $6.67\times {10}^{-4}\text{Wb}$
• B. $3.67\times {10}^{-4}\text{Wb}$
• C. $6.67\times {10}^{-3}\text{Wb}$
• D. $3.67\times {10}^{-3}\text{Wb}$

Answer 1

The correct option is A $6.67\times {10}^{-4}\text{Wb}$

${\varphi }_{\text{coil}}=\left(N\varphi \right)\propto i$
$\Rightarrow \frac{{\varphi }_P}{{\varphi }_Q}=\frac{i_P}{i_Q}=\frac{3}{2}$
$\Rightarrow {\varphi }_Q=\frac{2}{3}{\varphi }_P=\frac{2}{3}\times {10}^{-3}=6.67\times {10}^{-4}\text{Wb}$
<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Hence, $\left(A\right)$ is the correct answer.