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