A circular coil of thin insulated copper wire, $$N = 2000$$ turns, wrapped around an iron cylinder of cross-section area $$\Delta S = 0.001\,\text{m}^2$$, is connected to a suspended type moving coil ballistic galvanometer. The suspended rectangular coil of the galvanometer is of mass $$m = 80\,\text{g}$$, length $$\ell = 5\,\text{cm}$$, breadth $$b = 3\,\text{cm}$$ and has $$n = 100$$ turns of fine copper wire wound on a non-metallic frame of ivory. This rectangular coil of the galvanometer is free to execute torsional oscillations in a radial magnetic field $$B = 0.1\,\text{T}$$. The galvanometer is being used to measure the charge by employing the formula $$q = \frac{T}{2\pi}\frac{c}{nAB}\theta$$. Given that the moment of inertia of the oscillating coil about the vertical axis is $$I = 2.7\times10^{-6}\,\text{kg m}^2$$ and the torsional constant, torsional rigidity, of the suspension fiber is $$c = 3.0\times10^{-3}\,\text{N m rad}^{-1}$$. The area of the coil is $$A = \ell b$$. When the magnetic induction of $$1.0\,\text{Wb m}^{-2}$$, perpendicular to the plane of the circular coil, is reversed in opposite direction, a deflection of $$40\,\text{mm}$$ is observed on a scale placed $$1.0\,\text{m}$$ away in front of the reflecting mirror attached with the suspension fiber of the rectangular coil. The correct statement or statements is or are