Question

The self inductance of a closed-packed coil is $8\text{mH}$. A current of $5\text{mA}$ is passed through it. Find the magnetic flux per unit turn of the coil, if it has $100$ turns.

• A. $2\times {10}^{-7}\text{Wb}$
• B. $4\times {10}^{-7}\text{Wb}$
• C. $2\times {10}^{-6}\text{Wb}$
• D. $4\times {10}^{-6}\text{Wb}$

Answer 1

The correct option is B $4\times {10}^{-7}\text{Wb}$

The self inductance of the coil is,

$L=\frac{N\varphi }{I}$

$\Rightarrow \varphi =\frac{LI}{N}=\frac{8\times {10}^{-3}\times 5\times {10}^{-3}}{100}=4\times {10}^{-7}\text{Wb}$

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