a. A piezoelectric sensor has capacitance, C = 800 pF. The sensor leakage resistance is 1 OGfi. The amplifier input impedance is 4MQ. (i) What is the low-comer frequency? (ii) To detect a certain pulse, the frequency has to be extended to 0.05 Hz. What size shunting capacitor should be added? b. A capacitance sensor with plate surface area, A = Icm^ has resistance, R = 100 MQ. The sensor will be used to detect a certain audio signal. (i) What is the capacitance required for the sensor to detect signals above 30 Hz? (ii) Calculate the plate spacing, x, required to obtain this capacitance value. (Dielectric constant of free space, e = 8.854x10"^)