$=\frac{\mu_{0} \cdot x ^{2}}{2 \pi \times 0.2}$
$F =2 \times 10^{-6}=\frac{4 \pi \times 10^{-7} \times x ^{2}}{2 \pi \times 0.2}$
$\Rightarrow 10^{-6}=10^{-7} \frac{ x ^{2}}{0.2}$
$\Rightarrow x ^{2}=10 \times 0.2$
$=2$
$\Rightarrow x =\sqrt{2} \approx 1.4\,Amp$

$\overrightarrow{\mathrm{F}} =\mathrm{q}(\vec{v} \times \overrightarrow{\mathrm{B}})$
$=\mathrm{q} \vec{v} \times\left(\mathrm{B} \hat{i}+\mathrm{B} \hat{j}+\mathrm{B}_{0} \hat{k}\right)$
For $\mathrm{q}=1$ and $\vec{v}=2 \hat{i}+4 \hat{j}+6 \hat{k}$ and
$\overrightarrow{\mathrm{F}}=4 \hat{i}-20 \hat{j}+12 \hat{k}$
What will be the complete expression for $\vec{B}$ ?
