The expression for the capacitance (C in pF) of a parallel plate capacitor is given by: \(C = 6.94 \times {10^{ - 3}}\left( {\frac{{{d^2}}}{s}} \right).\) The diameter (d) of each plate is 20 mm and the spacing between the plates (S) is 0.25 mm. The displacement sensitivity of the capacitor is approximately.