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(a) A weighbridge is used to measure the mass of a road vehicle and hence monitor overloading. The designer of a new weighbridge is considering two different sensing modality options. The first of these is a capacitive based design, with rectangular plates of dimensions (2.5 x 6 m), shown in Figure Q2A with a dielectric spacer of relative permittivity (R = 1.5) and plate separation (x) in mm. x mm Capacitive Weighbridge 2500 mm 6000 mm Figure Q2A Permittivity of free space εo = 8.85 x 10-12 Fm-1 i) Calculate the measured capacitance (CM), between the load and the base plate, with plate separation (x) of 80, 100, and 120 mm. ii) State if, and explain why, the variation in capacitance is linear or non-linear as a function of plate separation (x). 4 marks