For a moving coil galvanometer, the deflection in the coil is 0.05 rad when a current of 10 mA is passed through it. If the torsional constant of suspension wire is $4.0 \times 10^{-5} \mathrm{Nm} \mathrm{rad}^{-1}$, the magnetic field is 0.01 and the number of turns in the coil is 200, the area of each turn $\left(\right.$ in $\left.\mathrm{cm}^2\right)$ is