The magnetic field at the centre of a wire loop formed by two semicircular wires of radii R_1=2 π m and R_2=4 π m, carrying current I =4 A as per…

The magnetic field at the centre of a wire loop formed by two semicircular wires of radii $\displaystyle \mathrm{R}_1=2 \pi \mathrm{~m}$ and $\displaystyle \mathrm{R}_2=4 \pi \mathrm{~m}$, carrying current $\displaystyle \mathrm{I}=4 \mathrm{~A}$ as per figure given below is $\displaystyle \alpha \times 10^{-7} \mathrm{~T}$. The value of $\displaystyle \alpha$ is $\displaystyle \_\_\_\_$. (Centre O is common for all segments)